Here at my house we have three desktops, two different kinds of netbooks, and a laptop running Kubuntu. They all have two things in common:
1. They all have Intel graphics of one variety or another.
2. None of the work very well (or at all) with Kwin compositing in Maverick.
These appear to be mostly properly blacklisted from compositing to start with, but the thing is, they all work with compositing just fine on Lucid (the upstream Kwin solution to compositing issues with KDE 4.5 is to make sure the black lists disable compositing where it won’t work well and that generally works). The problem is (from my perspective) that I have a beautiful, functional composited “desktop” in Lucid with KDE 4.4 and to move to KDE 4.5 in Maverick and lose that would not be an “upgrade”.
None of my hardware is cutting edge for Intel. The newest is i965. I have one of those, four i945 variants, and one i865. It may be that newer chips are fine, I have no way of testing.
Personally, I find this extremely demotivating. After investing a truly ridiculous amount of time and effort into Kubuntu development, I discover at the end that I literally have no systems I can reasonably run it on (my servers are staying LTS anyway).
I’m posting this as a warning to people considering upgrading. Don’t just upgrade, burn a live CD and try it out first. Make sure you’re happy with the graphics performance.
P. S. The current KDE in Maverick, 4.5.1, is the one we will release with. If you want to know why 4.5.1 instead of the usual 4.X.2 we’ve released with for the last four release cycles? It’s because 101010 binary = 42 decimal. Enjoy the extra bugs.