well i only know from expirence about 2 of them and that is the iPhone and the Droid. I currently have a Droid and in my opinion I like it a lot better than the iPhone... when I had the iPhone 3G it did not hold up at all. The screen is very delicate which is a difference with the Droid. The Droid holds up much better. Though I have no expirence with the Samsung, I do have their TV and computers. I really like those and they have good quality.
IPhone all the way!!! Better graphics. Better touch screen. Every droid I had got messed up. I'd go to click something & It would end up opening an ap on the other side of the screen. The battery really isn't that bad. Unless you're on the Internet all day. But that's like all other phones. More apps. Faster & looks better. It is more delicate but just get a good protective case & you should be set.