Yeah android only.
The new UI.
You can like/thank posts (which isn't even enabled here anyway, which is lame).
Better image viewing support.
Account syncing across devices.
The ability to upload images while making posts.
A better notification system for PMs subscribed threads.
Some other minor stuff I can't remember right now.
I think once they're done catering to the android master race they're going to work on the iOS version, but it'll probably be a while yet. And then they'll have to go through the app store review process (lol).