for now the question is which OS u preferred? dun even try to compare ip4 and sgs2 specs to justify ur purchase. these 2 models are from different time period. and btw, ip5 is coming out soon this year

in short, do u like simple interface? or do u like to customize everything? if u r lazy and normally go with stock options, take ip4. else take sgs2 for customization. just my 2cents