I personally like the new interface, though it took a while for me to get used to the new layout.
I do encounter one bug. I am no longer able to navigate to the "manage pages" page (wp/wp-admin/edit-pages.php) it states that the page is no longer there. I check to see if I accidently deleted the page in my FTP program but the document is still there.
It was working fine up until yesterday... so perhaps I just haven't quite remebered all of the things I was messing around with yesterday. Unless omsone else encounters something similar - I'll chalk it up to user error. Just thought I'd post it incase anyone else has ran into this.