Android is really customizable unlike an iphone. The iphone is not customizable at all other than the wallpaper. On an android you can redo your whole hi in just minutes without having to perform any type of hacking.
First, of all you can change your wallpaper, which can or cannot scroll with your screens. And on your screens you can have widgets which you cannot have on an iphone.
Second you can get a custom launcher. This is your used interface, so if you are buying a phone and it says it can have up to 3 screens, that's a lie, you just get a launcher and you can have hundreds of screens. So if you hate HTC sense or Samsung touchwiz, get a launcher such as go launcher ex. A launcher can let you customize or your status bar, and even ad screen transitions, icons appdrawer and really sometimes nothing and sometimes everything. You can make your android feel and look like an iphone or a windows phone simply by downloading an app. Also, for example go launcher ex, probably one of the most customizable launchers out there, has a guide of 5000+ themes.
But that's not all, with go launcher ex, widgets are themeable, each icon is themeable.
And also you can change your keyboards, and theme them to from hundreds of themes.
Ha, i want to see iphone do something like that without a jailbreak which will slow down your phone unlike an android root such speeds it up.
Screenshots, 1: launcher 7 ui, 2: zeam launcher, 3: stock LG launcher.