I would rather call it "evolutionary" but now Apple has to go back and tighten up the nuts and bolts on the new buggy.

Like the double-click on the top of a window not dropping the window onto the dock like it used to (yellow button still works).
The Migration Assistant messed up tons of file permisssions when I transfered data and apps to a new Macbook Pro from a Powermac G5, resulting in a fresh erase and install, and manual app installations - 4 hours of mind nimbing work! (filed with Apple Care, who acknowledged the problem)
Other people are having network problems, etc. etc. As usual in a 10.x.1 release, there are many rough edges left to file down. I expect things will smooth out by 10.6.7 or 8. I do like the overall feel of the system, just wouldn't call it an epic win. But I do think it will be a winner in time.