I see that most users here prefer a Nexus 4 over Samsung S3. I own both devices, and Galaxy S3 is still my main device, with reasons below:
1. Praise pure Android experience, while trashing Samsung TW UI. This is by far the most arguments I've seen. What I don't understand is, if you don't like Samsung TW UI, use a launcher like Apex solves the problem completely, you can make the UI look almost exactly like the "pure android experience", well, maybe not the setting page, but does that colored setting icons bother you guys that much?? The added Samsung functions really do add some nice touch to the Android system, like double tap on the Home button to bring up S voice, is rather nice. You can't do that on Nexus 4. OK, how well does S voice work is whole new different topic we shall not get into details here, but I found it works fine with simple commands like: "Navigate to Bestbuy", or "Set alarm at 5pm", etc. The swiping palm to take a screenshot is also very neat, my personal favorite is the toggling from the drop down notification area, it makes turning on Wifi, bluetooth, etc so much more easier, even better than widgets. There are a lot more features that are considered "gimmicky", but one should not rate the device down because of the added feature. You can always completely disable these features.
2. The aesthetics of the phone. Now N4 is not a bad looking device, it's just not good enough to turn heads. With my white S3, I get a lot of compliments on how good the phone looks. Who cares it's all made of plastic? I mean no ones is gonna value your phone more because of the material been used. The massive number of S3's owner base tells you S3 is a good looking device. The mainstream population buy phones that are looking good to them. Iphone is another prime example, please do not flame me on this one, the fact is most people buy iPhone because of its good looks.
3. Now the screen, I looked at both screens really hard, and found both screens to be gorgeous. It is really a personal preference if you prefer the the warmth, slight yellow tinted S3 screen, or the more neutral color of N4. Samsung S3 appears to have deeper black to me, and N4 wins on the clarity of text. That's not to say S3 has blurry text, or N4 with gray blacks, it's all relatively speaking.
4. Speed, OK, N4 is faster, no doubt about that, the specs says so, and it shows in real usage too. When I use Go EX launcher I can feel a very slight lag on S3, but none with N4. But if I stop using Go launcher, I don't find any lags with S3, opening or switching between apps I can hardly find difference between the 2 phones. Overall, I'm pretty satisfied with S3's performance, although N4 is a faster device.
5. Camera. S3 wins hands down on this one. Not sure for those who can't tell a difference, S3 takes quicker, sharper pictures, and also better in low light performance. I find the Camera interface is light years ahead of the clumsy Android 4.2 camera UI. The Samsung camera UI is clean, intuitive, and full of features. Where as that circular option of Android camera, it's a nightmare to use, the earlier version of Android camera apps are even much better, IMO.