I've got one at work. It runs CS3 alright so long as you aren't running much else.
For instance, I'm always running: Firefox, Adium, Entourage, Smart SVN, and TextMate. If I turn on Photoshop, it's no problem. If I turn on my Windows XP Virtual Machine, it's no problem.
If I turn on Photoshop and the XP Virtual Machine...it's like clicking through molasses. Photoshop regularly uses 500MB of RAM by itself.
Sadly, I'm a bit underwhelmed by the performance of this Mac. My Vista machine does just as well with lower processor specs (but higher RAM - 3GB instead of 2GB). OS X is nice, though. It's pretty and once you get used to it, it's usable. Still prefer Explorer to Finder, though.