I love in particular that the list is sorted in an alphabetical order. It is not exclusive to the Gmail.app for iOS but in the web GUI, it wasn't available a few months ago. If you added an additional mail addresse, the order within your address list sometimes even changed.

I would of course still prefer if I could define the list order (as in Mail.app for iOS and OS X) but an alphabetical order is still better than a more or less random order … :)