The overwhelming command for the iPhone 4S is explicable, known the much-talked-about Siri voice-controlled fan, as well as the strategy faster dual-core processor and fantastic 8-megapixel camera. But today's summit Android phones--such as the Samsung Galaxy S II--offer plenty of features you won't find on Apple's runaway success sequel. How do you know which side in the direction of choose?
Try both Android and iOS out yourself is the only true way to know. You can read all you want about the pros/cons of both, be nit picky down to the smallest specs, but nothing beats hands on experience.
Look at features you "really" care about. There are lots of bells and whistles for any device but usually it doesn't matter too much because you don't really utilize it. Buy what you use today, not what you will in the future. Technology changes at the blink of an eye.
IMO iphone or galaxy, its just down to personal preference both are solid.