Android is great in that they are open, but their UI library is really just a mess, anybody who uses it for any amount of time yearns for the days of laying things out using HTML. iOS is much better in this respect but has the problem of limited devices and of being a closed platform.
I have no idea how they B2G (Boot2Gecko) will navigate the patent minefield, but I hope they do. I'm picking up another Galaxy Nexus just so I can have a phone dedicated to hacking on it.