I have both a 4s and an android phone, and while apple has more apps, and definitely more/better games, more isn't always better. Some of the apps are more polished on apple, but most of the popular apps exist on both, and I've not found anything an apple app can do that I couldn't get on android. BUT.. there are a LOT of apps on android that do things that apple can not do(unless you jailbreak - but even then its still not as open as andriod).
On andriod, you have full access to your file system, so you can just browse all your folders like you do on pc, you can browse your lan over wifi, and copy to and from shared folders.. Apps have the ability to access the file system, as well as other apps, so if you take a picture in one app, you can open it in another to edit, then share it via tons of online services. With IOS5 they've added the share via twitter thing, but in general on android its a lot easier to work with media.
I think the Iphone's camera takes better pics in general, and the 4s has excellent video capabilities. Overall, I think if you're into geeky tinkering, and making your phone do uber cool things - go android.. if you just want a smartphone that does regular smartphone things, then both phones will suit you just fine.. they're both really good.