The short version: if you're on T-Mobile, or wish to switch, this is the only phone worth buying, period. It blows away the competition, including the Galaxy S III, and my previous pick, the Galaxy Nexus. It's also $300 off-contract, which is absolutely nuts for a high-end cellphone, most of which retail for $600 and up off-contract.
The longer version is much more nuanced. This phone is so amazing that its many minor flaws jump to the surface. I'm going to be incredibly critical in this review of its flaws, but please don't think this implies that I do not like the device. Indeed, I'm very, very happy with it, and wouldn't trade it for any other phone that has been created at time of writing.
Looking at the Nexus 4 and the Galaxy Nexus side-by-side when laid face up on a table, there are very few differences. They are both elegant, unadorned black slabs, with the same fairly unique rounded top and bottom featured on the Nexus S. They both have a roughly 4.7" screen with no hardware buttons. Google has defined how a Nexus phone ought to look.
When you pick up the device, however, the difference in build quality is incredible. Though the Galaxy Nexus was a fair step up in this regard compared to the utterly cheap-feeling Nexus S that preceded it, the Nexus 4 is in a different class. It feels incredibly sturdy and rigid in the hand. The glass back and rigid frame surrounding it look and feel great, if a hair heavier than its predecessor. I like the feel better than the iPhone 4/4S, as the edges are tapered rather than straight, and covered by an extremely pleasant soft-touch material. The front glass is curved on the edges, and is wedded to the frame with a dark glossy plastic rim. The curved edges of the glass feel really great, and make swipe gestures feel a little more natural. This is in a similar (but not quite equal) class of design that we're used to seeing by Apple, HTC, and Nokia.
Not everything is an improvement over the Galaxy Nexus, however. The power and volume buttons, though in the same locations on either side of the device that have been the same since the Nexus S, have a cheap, plasticky feel, and are more difficult to actuate. The headphone jack has been moved to the top, which is awkward when I want to have both a USB cable and headphones plugged into the device at the same time (which I do almost every day on my commute to work—tethered to my laptop to provide internet access while I'm listening to a podcast). Like the Galaxy Nexus, the Nexus 4 has its speaker (unfortunately) on the rear of the device. However, as the Nexus 4 has a perfectly flat back, when sitting on a table, the speaker is almost completely muted. Why do no high-end phones have front-facing loudspeakers? This is preposterous to me.
And though the whole device looks and feels fantastic, it really could be better. The glass back, while adding rigidity and maintaining RF transparency, makes the device more fragile, and more slippery. I've caught it several times slipping off a not-too-level smooth table. Why couldn't Google have opted to ditch the glass rear, and have a milled polycarbonate back that continued the soft-touch material it used for the perimeter of the device?
The shiny plastic rim that provides a transition between the front glass the soft-touch sides is completely unnecessary, and makes the device feel cheaper than it ought, and looks like it will eventually scratch/chip the layer of paint that keeps it glossy.
Finally, while I was pleasantly surprised to find the large size of the Galaxy Nexus comfortable, the added size to the Nexus 4 is actually a detractor. Google made the screen wider in portrait view, and it now is just barely uncomfortable to use in one hand. As the entire industry seems to race for larger and larger devices, a trend which I've generally applauded, my hands are dictating a maximum threshold.
The screen on the Nexus 4 is really incredible. It's crisp and clear, and feels even closer to the surface of the glass than the screen of the Galaxy Nexus. Though I raved about the Galaxy Nexus screen in my review last year, after a few additional months, the weaknesses of the screen just became more noticeable, primarily the Pentile (RGBG) subpixel arrangement. Though I still prefer the contrast and deep blacks on AMOLED screens, the LG Nexus 4's screen is truly excellent. It's crisp and sharp. The viewing angles are very good. The iPhone 4/4S/5 and the HTC One X still have slightly better screens, but the screen on the Nexus 4 is excellent by any measure. The biggest complaint I have is the somewhat muted, washed-out colors. My guess is this is due to poor post-assembly calibration. I'm hoping that future builds of CyanogenMod will allow me to adjust this myself, but it's a shame that an otherwise great screen shipped with such an easy-to-fix problem.
The touch sensitivity of the screen seems to be a hair lower than the Galaxy Nexus, particularly around the edges of the device. I find it takes more effort to pull down the notifications tray than it does on other devices.
The screen is slightly wider (in portrait mode) than the Galaxy Nexus, making it impossible for me to reach across the device with my thumb. Adding an additional 58 columns of pixels really hampered the usability of the device. However, everyone's hands are different, so your mileage may vary.
Performance and battery life
This is the one place that I will have absolutely zero complaints. Whereas the Galaxy Nexus was possibly the first Android phone to feel "fast enough", the Nexus 4 is simply fast. The Qualcomm Snapdragon S4 Pro is really, really fast. Like iOS fast. Zero lag. Qualcomm's Krait, an out-of-order, 4-issue ARMv7 implementation, is not only incredibly quick, but it also sips power. The bundled Adreno 320 is an excellent GPU, finally providing Qualcomm with a part that can stand up against Exynos 4 and Tegra 3 on all counts. The only SoC's that can really stand up to the S4 Pro are Samsung's Exynos 5 (ARM Cortex A15 + Mali T-604) series and Apple's A6 (Apple Swift + PowerVR SGX-544MP).
The battery life is very, very good. On an average day, I have more than 30% charge left when I go to bed. On heavy use days, it's about the same as the Galaxy Nexus. On light usage days, it's worlds better. This is partially due to the 2100 mAh battery in the Nexus 4—it's just got a lot of juice. But also due to the Snapdragon S4, which sleeps very well. On the three nights that I'd forgotten to plug the phone in before bed, I woke up and found the phone lost only 2 or 3 percent of its charge. On the Galaxy Nexus, this would have been about 20%. It's far from the insane battery life of phones like the Motorola RAZR MAXX HD and the Samsung Galaxy Note 2, but it's good enough for the average work day in NYC, at least for me.
The camera, much like the Galaxy Nexus, takes fairly mediocre pictures, but does so extremely quickly. Although I really don't take many pictures from my phone, it's unfortunate that Google didn't choose to up their game in the face of competition with the Galaxy SIII, One X, and iPhone 4S/5. However, the phone is $300 on contract, so I guess something had to give.
Like the Galaxy Nexus, the Nexus 4 has a pentaband HSPA radio, and operates on T-Mobile, AT&T, and the majority of GSM carriers worldwide. This is the best phone to travel with in existence. The downside that it doesn't support LTE. For T-Mobile and most international users, this is fine, as T-Mobile doesn't have an LTE network yet, and its HSPA+ speeds are quite good. For AT&T user, that means this phone is all but useless in major metropolitan areas, as HSPA is mostly useless. Well, with premium parts like the screen and SoC, to hit the $300 price point something had to give.
T-Mobile is, however, promising to roll out LTE to 200 million users in 2013, and some have found that the Nexus 4 has a latent LTE radio that supports at least one of T-Mobile's bands. We'll see what becomes of this in the coming months.
Software — Android 4.2 Jellybean
Jellybean is a nice upgrade over Ice Cream Sandwich. It's much faster and more responsive, and gets rid of the animation jitter, primarily by implementing system-wide triple-buffering and vsync.
The real star feature of Jellybean is Google Now. Some people have billed this as Google's answer to Apple's Siri, and while that's somewhat apt, it doesn't tell the whole story. Google has had voice recognition, dictation, and search in Android since Android 1.5, and it was always a major competitive advantage. Apple's Siri, released last year with the iPhone 4S, not only filled that gap in its own ecosystem, it also aimed to become more of a personal assistant. Whereas Google Voice Search simply returned search results, Siri would try and actually answer questions and do things for you. Google Now is also a take on the "personal assistant" role, but it goes about the task very differently. It integrates multiple data sources Google already has access to, such as Gmail archives and your browsing history, but also logs different things you do and places you go. When I first upgraded to Jellybean (4.1) on the Galaxy Nexus, it took 3 days for Google Now to figure out where I live and work, without me telling it anything. It just used my real-time location data to figure it out. It perpetually tells me how long it will take to get home by train, warns me of weather alerts, tells me when I have to leave the house to get to my first meeting of the day, and many other incredibly useful things. Useful, but a little creepy. It's really, really handy.
The voice that the whole system speaks in, whether in Google Now, Google Maps turn-by-turn directions, or text dictation, is really, really good. It sounds significantly clearer than Apple's Siri, and speaks quickly, so an impatient, chronically busy North Jersian like myself gets a bit less frustrated.
And that's basically it. Sure, there are tweaks all over the system, and nice little conveniences, but there isn't much that will surprise you if you've already used Ice Cream Sandwich. The most remarkable thing about the software on this phone is that it's just plain Android—no carrier or OEM bloatware. That really shouldn't be remarkable, but it is. The crap shoveled onto Android by Samsung, HTC, Motorola, et al., is just big, bloated, and obnoxious. Though this phone loses in some synthetic benchmarks against the likes of the HTC One X and the Galaxy SIII, the whole experience feels so faster on the Nexus 4.
The biggest improvement on the software side over the last year has been the app ecosystem for Android, largely due to Google's new focus on design with the Holo theme, improvements in the developer tools, and the Android Design Guidelines. Android applications on average aren't as high-quality as their iOS counterparts, but the gap is narrowing. I don't see it truly catching up soon, mostly because Android users seem much less willing to pay for apps than iOS users. Plenty of great games are coming to Android and play very well on ICS and later with decent hardware.
New entrants, like Press, The Verge, and Eye in the Sky take the Android design guidelines to heart and build cohesive, native applications, whilst existing apps like Dropbox, Pocket, and Rom Manager redesigned to follow the UI/UX direction that Google is traversing now, and to great effect. Press, in particular, really sets the bar for fit and finish in a non-Google app in the Android ecosystem; it's the first Google Reader client that is as attractive and functional as the legendary Reeder for iOS. The only area where I'm constantly disappointed is Twitter apps. There's really nothing on Android that can compete with TweetBot or Twitterific. The best I've found is Tweet Lanes, which is excellent but incomplete, and sadly was abandoned by its developer due to Twitter's new terms of service which basically prevent anyone from making any reasonable amount of money selling a Twitter client.
As I stated earlier, if you're on T-Mobile, this is the only phone you should buy, period. T-Mobile, as of this writing, there is no model of the iPhone that supports AWS, so your choices are Android, Windows Phone, and Blackberry. Let's be honest: only one of those is worth considering for a primary phone. It is not a perfect device by any means. Unlike last year's Galaxy Nexus, it's not available on every carrier, it does not have LTE, and it isn't the only Android phone out there with competitive hardware.
But it is really fast, has a great screen, great battery life, and stock Android with updates directly from Google. And it's $300 off-contract, which means you can pair it with T-Mobile's $30/month plan with 100 minutes, unlimited texts, and unlimited data. Or if you're a heavy voice user, go with an MVNO like Simple Mobile, which offers unlimited voice/text/data for $50/month on T-Mobile's network. It's a really great deal on a really fantastic phone. It's also the best phone to travel internationally with overall, as it supports HSPA bands in a large number of countries.
Sadly, I can't recommend this phone to any users of any other US carriers. You can use it on AT&T, but you won't be happy with the data service, particularly if you're coming from an LTE phone.