So far so good! I like the new interface, and it feels slicker and more modern. Particularly, I think the animations in the sidebar give a nice impression, and the rest of the UI feels more responsive. That may just be the lack of loaded plugins. It also suits Windows 7 a little better, and feels a little more like a ‘native’ Win7 app; the groups feel like they’ll match the Windows Explorer left-hand panel’s idiom of Favourites / Libraries / Homegroup / Computer.
I’m guessing that the left hand bar will be full of other buffers and suchlike? I’d quite like to see things like the console output displayed as full-size buffers, rather than small windows which don’t get treated as ‘proper’ panels. The same way emacs dumps everything into new buffers.