Well, as they say, it is different under the hood and that's the only thing I care about.

I know how it behaves on Android and Gmail, so I don't understand where the need of abandoning XMPP comes from (other than restricting users to use their OS, just like Microsoft has been doing for ages).

I use Talk mostly on Maemo (integrated messaging) and KDE desktop (ktp in the panel - nothing beats this), only occasionaly Gmail, webOS, Android... So I'm surely gonna feel this change.