It works better on wide screens. This is pretty obvious. The old one took up a puny little side area of my screen. Totally not efficient.

It's awesome how you can comment on pretty much everything. Before, you could only really do this for posted items and notes. Now you can comment on added friends, statuses (this is a HUGE plus), things you do, etc. I only wish it also let you comment on another person's wall post...

The new home page is awesome. The new ways to view news by application, friend group, etc. is pretty neat. Plus the "Live Feed" feature lets people stalk (err...keep up to date on) on friends.

It is organized better. This is probably the point a lot of people will disagree with me about. I guess it has a lot to do with personal preference. For me, I think the way they made it easy to edit your profile/wall settings while on the same page makes a lot of sense.

Applications are easier to manage. Now all your applications can be viewed in one nice, neat little list with stars next to them if they're bookmarked, etc. And you can mass-edit permissions. I'm not so sure why they moved the applications tab to the bottom left, though. It was fine on the upper bar.