I really like it overall. Just a couple things annoy me:
1. The only way to distinguish the tab in focus from other tabs is the red x for close, and sort of by the bold text. Maybe make it glow?
2. Google Toolbar doesn't work well, because the typing/search window text is very dim. Address and Search bars are nice and bright in Firefox itself - not sure how you'd address this.
Like I said though - overall it's great, and I'm using it now, and I like it.