I tried Kubuntu 8.10 recently and was less than impressed with the buggy functionality and lack of polish in places. Having tried a number of prior versions of Kubuntu in the past I have to say my conclusion is still the same. Canonical concentrates the bulk of its efforts on Ubuntu and it shows. This is not to disparage Kubuntu developers, not in the least. It’s just that the more pairs of eyes examining and testing the code, the faster they can track down and fix any issues. And I’m sorry to say it but Canonical focuses mainly on Gnome.
I compared Kubuntu 8.10, Mint 6, PCLinuxOS 2008 “MiniMe” (KDE3), and openSUSE 11.1 over the last month. IMHO openSUSE 11.1 has a much better implementation of KDE4 than Kubuntu and a more polished interface than any of the others I tested. It uses KDE 4.1.3 and actually backports a number of features from KDE 4.2 (to be released in 3 weeks btw) for fuller functionality. While Gnome has come a very long way since the last time I test-drove it, I find KDE still has more robust utilities and interfaces. So despite my preference for Adept, I’ve switched to openSUSE and so far am quite pleased. Mind you, if you want restricted formats you’ll have to install them separately, but the openSUSE community has a one-click install here. Very convenient.
As I’ve mentioned before, GNU/Linux still has a way to go before it is polished enough for the masses. But it’s definitely getting closer.