I have been playing around with XFCE4 on Kubuntu for a couple weeks now. I have looked at some config files, tried a little theming (very little), and basically poked around some of the config util GUIs. It is quite fast to start up, and most functions are available that I had in KDE (konsole acts weird when I run it, but that is almost certainly my doing). I do miss the customizabililty KDE has, however. One thing that really confounds me is the apparent difficulty in having a different wallpaper for each desktop workspace (as shown in pager). The default system approach seems to be one wallpaper for all desktops, and I have no idea how to change this. There are some other things to learn as well, like using Launcher to add programs from a menu to a taskbar, whereas in KDE, you would just drag-n-drop or right-click and Add from one of your program menus.
Anyway, not gripes, just observations. It is pretty cool, and I like it enough to keep on playing with it. I certainly do not mind having to edit or even create a config file or three along the way – sounds like fun to me! I still prefer KDE – it has never been “slow” on any of my systems (one of which is quite old), but XFCE4 is a nice diversion and so far, one worth the effort. More to follow later, I guess.
Oh yeah, before I run off, I installed it using Adept, while in KDE – I looked for the XFCE and Xubuntu packages, and installed them that way. Then I logged off and logged back in, choosing XFCE instead of KDE for the desktop environment.