Well, it seemed to work well enough on the DP1.0 I just tried it on. No noticable speed changes (complete startup takes 1:20, but it did before, too), didn't fix the drifting text in Camino issue, but in a very quick test the cross platform network here seems to be running more smoothly. A bit slow, but smooth.
Oh, and no non-preexisting permissions issues--just some with the Flash plugin that were probably there before.
I'll hold off upgrading my G5 for a little bit, at least till the combo updater is out (hope there is one).
I wonder if those complaining about app lauch times are just getting confused because they're LAUNCH times instead of RE-LAUNCH times. That is, apps always start much faster the 2nd time, but if you rarely shut your computer down you might forget this. Since you by default did shut it down for the update, you could be seeing the first launches and thinking it's actually slower.
Even my first launches are ok, and 2nd launches are one bounce or less on Safari, Mail, iTunes, BBEdit Lite, QT Player, Sherlock, Word, Terminal, and Address book. Heck, even Acrobat Reader 6 only takes a fraction longer than a bounce to pass the boot screen.