I compiled KDE4 two days ago as well, and so far like it. Even the desktop effects worked, when I tried them for a little while.
But there's one thing that quite annoys me - konsole is EXTREMELY slow, switching from tab to tab takes more than 1 second, fast scrolling is impossible and if I minimize it, it takes the same amount of time to redraw the part of the screen that was below konsole. When I was playing around I noticed, that it was only this extreme when I was using a bitmap font (terminus) - when I used DejaVu Sans Mono, it was noticably faster, but still not perfect.
The thing is, shouldn't the bitmap fonts be the faster ones as they don't need font smoothing?
