Everything. It has the same "drop and zap" setup as before, but then it has a toggle that shows you all your apps (with tabs for other things, like plugins and prefpanes), and then it has filters to show apps you haven't used in the past x amount of time, and then you can sort them all by size or name or last used.
Now that's an amazing huge usability upgrade, but it's the polish and animations of it that blew me away. Apps reorganize themselves when you change the filters and sorting, the sliders fade in and out beautifully. It's also 64 bit, obviously, and Snow Leopard exclusive, per the upgrade changelog message.
It's seriously gorgeous, and I feel like a dork for raving about it, but it's honestly deserved.