One troublesome aspect of Android phones (no experience with iPhones) is that updates come bundled as huge releases. I have an original Motorola Droid, and it received huge updates over the air. This seems backwards given the history of modular Linux distro management. If the kernel is updated, send a kernel update. If the browser needs an update, send a browser update. I think there's much evidence that the 'service pack' model of security and bug fix management doesn't work well.
I've since moved the phone to Cyanogen. Now I'm responsible for keeping it up to date, though sadly Cyanogen doesn't appear to do per-problem updates either.