The new UI is a big improvement (I like the new combined control very much indeed), and it looks glorious on my 20" iMac G5. Since it's a Universal binary now, Intel Mac owners are sure to notice a speed improvement (although Rosetta was not the major bottleneck).
The free edition of SketchUp for the Mac was also available, and it is a superb toy - I used it quite a few times for rough drafts of 3D models, and it never ceases to amaze me how easy it is to sculpt stuff in it.
Update: Being inside my admin account running Software Update (I prefer switching over to it to do installs and general housekeeping once in a while), I hadn't noticed the MindVision installer for SketchUp was so crappy as to bomb out without administrative privileges - as per AJ's comment, I ran the installer on my iBook and yes, sure enough, it failed. Bloody stupid, seeing as it comes from a company that ought to know better.