bored with the same operating system, theme, layout when you're stuck with it for as long as you own it? Apple have like 1 update in a year or two.
It's so great what Android can do for me, and/or rather what I can do with it. I can just flash and flash and my Galaxy SII will look like new (literally clean & well taken care of) and run like new (new/alternative roms, or the latest operating system).