8.10 beta is out. This is our big switch to KDE 4 so do test out the upgrade and let us know how it works. Read the announcement or go straight to the upgrade instructions.
You can leave feedback here or by filing bug reports or poking us on IRC.

Ooh, compositing by default.
Where do I whine about issues?
I rarely have whine-able issues with kubuntu. When I hit Finish in the upgrade wizard, nothing happens except "Cannot mix incompatible Qt libraries" gets printed (I ran from konsole w/ sudo rather than kdesudo).
:)
Congrats, Jonathan. Looking forward to Intrepid
Crashes in Akregator
Nice to see 8.10/KDE4 coming along, but I'm afraid some users will not be very happy when Akregator(4) crashes every single time with the same config files Akregator(3) parses just fine. Got this problem with KDE4-hardy packages (all versions up to 4.1.2), intrepid's, and Akregator(trunk). There's a bug in bugs.kde.org, I cannot remember its number now, but while this problem is not fixed, it will be too much of an anoyance to some users.