After playing around latest kubuntu 8.10, I found it totally difficult to adjust my mental phase into it. Even I've been heavy KDE user in times of 3.x versions, I found now 4.x very problematic. Somehow I could not handle dolphin as my file manager and desktop is not feeling like home any more.
I think that this might relate to the fact how KDE 4.x feels to the user, it feels like complicated to me as it currently is. I tried for month or so to adjust myself into KDE 4.x mode, but it was difficult. I felt my productivity decrease and after that I was forced to get back ubuntu 8.10.
Now my primary desktop has ubuntu 8.10 and in laptop I still have kubuntu 8.10. But it feels so much more better with ubuntu, I think I will switch back to ubuntu also on laptop soon.
Let you know how it gets :)