It's a big discussion if we compare their Features, attributes, Price, etc.
My opinion, don't prefer the S3 shape, rather go for S2.
for Note and Note2 (totally different class)!
Iphone (a lot to say!!!), shape is quite attractive.
A simple observation:
If you travel on tubes in London, you will find almost 50% have Iphones in their hands (average calculations, personally counted on different occasions).
I think, Iphone is not the just a smartphone now, It has become a BRAND, people like to have and add it to their personality, only my opinion.