When Google announced that the next Nexus will pack four Krait cores and an upgraded camera, all for the price of $300 ($350 for the more sensible, 16GB version), there was a short moment when it seemed that everyone after an Android phone would be crazy not to get a Nexus 4. It was better and cheaper than anything else out there.
Then reality interjected. Users realized the limited storage would be felt sooner rather than later, even in the "big" version. The vanilla Android just isn't everyone's cup of tea, the image quality isn't quite up to par, and there are a number of other things that are not ideal (non-removable battery for one).
Still, at $350 off-contract there's nothing that can compete with it (unless you're in China and know what Xiaomi Mi-Two is). The bad news is the price is not guaranteed. Countries where the phone isn't offered through the Play Store can expect prices in the €500+ range (and that's more than what the S III costs). It doesn't quite help either that the Nexus 4 is almost chronically out of stock.
The Samsung Galaxy S III has been on store shelves for months now and its price is fairly level across markets. It's also more flexible in terms of internal storage and has an LTE version, plus a home-baked launcher that easily beats even newer Android 4.2 in terms of features offered.
Its weak spot is that software updates will come slower, but Samsung has piled on a ton of exclusive features to make up for it. The Nexus 4 did manage to score big points for its excellent lockscreen and Photo Spheres feature, too, but overall the Galaxy S III software package is far more compelling.
Both phones have vibrant developer communities that will provide you with a steady stream of custom ROMs if the software of the two isn't quite to your liking (or if Samsung is taking too long to push out the next Android version).
It's probably not what you expected to hear, but the Google Nexus 4 will probably end up most popular with people looking for a mid-range Android. It's a class above mid-rangers but matches them on price - in short, you get far more than what you paid for.
It doesn't quite cut it for power users though - a high-end 3D game (the kind you'll want to play on a big HD screen and powerful GPU) can easily eat up a couple of gigabytes of storage and so can HD movies. And the camera just isn't a match for some of the competing 8MP shooters.
The Samsung Galaxy S III has a very good camera and its older chipset still has enough oomph for modern games (not to mention that its wider availability encourages developers to optimize their titles). Storage expansion is cheap and easy too - and you can opt for larger built-in memory. The removable battery lasts longer to boot. Then there's MultiView, which lets you put the big screen and quad-core processor to good multitasking use.
The holidays will soon be over and we expect the Google Nexus 4's supply to get back on track. If you have $350 in your pocket and are looking for a great Android phone, you can grab the Nexus 4 and tell Google "Nice doing business with you. Thank you very much!" That's if you can get it off the Play Store, of course.
The Samsung Galaxy S III makes up for the price gap between it and the Nexus by beating it in several key areas - it has a better camera, plenty of software tricks up its sleeve (we'd go ahead and call smart dial and Smart Stay must-haves) and more battery life. Plus, depending on where you live, there might not be a price difference at all.
Money shouldn't be of utmost importance it seems when it gets down to two of Android's finest. We enjoyed every moment and still cannot quite make up our mind. There're people on our team who would go for the Nexus even if they have to pay above the Play Store price. However, the diehard Android users among us tend to side with the Galaxy S III. There're some undecided but none who didn't care. We can bet that even people reading this on Retina displays are paying attention, even if they try to look like they have no dog in this fight.