First impression -
Flash MX wouldn't load up. It just kept automatically quitting after one bounce. Same with the 30 day trial of Flash MX 2004. However, after launching DW MX, Flash would start up fine. Strange.
Seems much more stable than b59, which I had a few quirky issues with (seemed slower than b53, and the menu items took a long time to load).
A nice touch (that was probably in previous builds but I just now noticed it)... in the ScreenSaver pref pane, you can search through your iPhoto albums... Very nice.
One thing I'm still not a fan of is either having the Finder with the sidebar using brushed metal, or in "Classic" mode with Aqua. This is wrong on so many different levels. As everybody already knows, I'm a fan of Path Finder, and will probably use that even with Panther is released. The quick journaled searching from the Panther Finder is quite nice though. Hopefully Steve @ Cocoatech will add that to Path Finder soon after Panther ships.