It’s very spacious, and somehow that’s not a good thing. For the most part, Facebook eliminated or de-emphasized side borders. There is still the right sidebar on the main page, but the left sidebar/ad bar was taken out in favor of a larger main column. Since the displayed content is dynamic, Facebook thought it best to play it safe and offer as much space as possible to accommodate. Doesn’t work too well.
Tabs are featured heavily, especially in the profile page. Are they useful? Of course, but now the pages seem cluttered and restricted despite the use of AJAX to eliminate much of the earlier clutter. I guess I don’t treat Facebook as a web browser so I don’t utilize the tabs too much.
Also the “Friends” box is no longer broken down by network, and is simply one large clump. Facebook is now becoming less niche network-like and more global network-like. I don’t dig that.