Well I would go for HTC One X plus cause its got beats audio and the camera is zero shutter lag. But the only prob is no expandable memory. Where samsung galaxy s3 has become an old phone now and it has some good features but I find it kinda outdated(my opinion). The iphone 4 is fast no lag at all but old. If you are looking for a smartphone you might as well try these amazing phones:-
1. Sony Xperia Z
2. Samsung Galaxy S4
3. HTC One