I recently tried the beta release of Tor Browser Bundle 3.0 and found both good and bad.
First of all, it starts up really fast. The old TBB could take a minute or more to start. Not anymore. This version starts up in just seconds. It's almost disconcerting. But it easy enough to verify that you really are using Tor, so that's great.
And since they obviously intend to treat this as private browsing "appliance" it just makes sense to consolidate and simplify the interface. For instance Vidalia had options for hosting hidden services or sharing bandwidth, but that made little sense when the whole thing is going to terminate as soon as you close the browser.
As usually happens, some useful features unfortunately got lost in the interface redesign. The main one I would miss is Vidalia's version of the "New Identity" command. Torbutton has a command of the same name, but it's different. It closes everything (without warning you, in fact) and restarts the browser. This is overkill if all you wanted was a IP Address (perhaps it was blocked) or a new circuit (bad connection). I think Torbutton should offer both commands, perhaps under the names "New IP Address" and "New Identity (Restart)".
Also, I had hoped tighter integration with the browser might mean that the bogus "Launch Application" warning had been fixed, but it's still there. On the one hand, it's just an annoying message, easily clicked away. But on the other hand, if it were true, it would be a very serious security warning. I don't think displaying something like that falsely should be taken lightly. I feel they're essentially training users to be careless by ignoring warnings.