My girlfriend has an iPhone. I started out with Android, so I always wondered if I was missing out on iOS. Just this weekend, I discovered 3 or 4 things that I really enjoy about Android that I wouldn't be able to do on iOS.
1. I wanted to add some songs to her iPhone, but because she was synced with another computer, I wasn't able to without erasing all of her music. With android, it would be as simple as dragging and dropping (or getting them straight from my dropbox account and skipping the computer all together)
2. Additional Keyboards. I love being able to text one handed, being that I use the elite swype keyboard. With iOS, that wouldn't happen. Another thing with keyboards, iOS apparently doesn't have a user dictionary? So I can change which words get auto corrected. That's annoying.
3. I know its simple, but I wanted to change the color of the text bubbles on my SMS app. I know its something simple and ultimately not that useful, but it's something I did with my android phone that I wouldn't be able to do with an iPhone.
4. Toggle buttons in the notification bar. This is specific to Touch Wiz phones (or cyanogenmod, if you flash roms) But I love being able to turn my wifi on without having to leave the app, or turn screen rotation off when I'm laying down in bed and don't want the phone to switch to landscape. With iOS, i would have to go to the settings app, find wifi, turn it on, double click the home button, and go back to my app.
Hopefully this information is useful for anyone debating the switch from one or the other, but I'm happy with android for now, and can't see myself switching in the near future.