Depends on the integration application as much as anything.

We're on Verizon. Your carrier matters, too.

I had pretty good luck with a Razr (because I hacked it and then used Motorola Phone Tools).

I had really bad luck with my daughter's LG Chocolate, because the Verizon/LG software sucks mightily.

I'm cautiously optimistic about my newish Palm Centro; it uses WMP and PTunes.

I don't think there is a serious rival to the iPhone in this regard.

bibere usque ad hilaritatem