i have recently shifted to S3 and during my decision i compared the following features
Screen Resoultion - S3 is way better than iphone 4s and HTC one X
Camera - S3 and one X are almost the same, 4s is behind on camera
Battery - S3 has a better battery life as compared to one X however 4S gives it a tough time
another thing which made my decision easier in terms of buying S3 was the newly added motion features ...... guys trust me they are the collest and it was a deciding factor for me !!!
I bought mine in Marble blue color although this one is some what rare to find and the shopkeepers in lahore have priced it higher than the white one but the liquid metal finish on the back battery cover IMO is worth the bucks