[PC-BSD Testing] I would think

[josiaslg]

in the install, give some option to use. something like "Choose Default WM", 
then KDE 3, KDE 4 or GNOME. In this way, KDE 4 bugs don't freeze the pcbsd 
devel team, that i believe, will just use KDE 4  as default when stable (not 
in *bsd, but all kde in self.). Leave KDE 4 just for "beta and test use"; In 
KDE 4.x or later version when is stable in many aspects, mark then 
"default".