I am on the Intrepid Minimal Installation. I currently prefer using LXDE due to its speed and ease of use.
Recently, I also installed XFCE 4.6 and it started-up extremely slow. I told myself that it must be because I got used-to the instantaneous start-up of LXDE.
And so, I installed the Kubuntu-desktop (Jaunty) and it started-up much faster than XFCE.
I have no benchmarks or tests but KDE also feels much lighter than XFCE.
Is there an XFCE bug that is slowing it down?
Although I am not really a KDE fan... I must say, KDE 4.2 is truly nice! I must say it is nicer than GNOME but I feel that GNOME's menu is more organized and easier for newbies.