I have found that people avoid xqf because they think it is slow to refresh. This is partly cause by people refreshing all of the main game instead of just servers for a particular mod.
Please add all the major mods in as master servers in the default config. Other server browsers already do this and I think it is helpful.
I'll start with Urban Terror for quake3:
Master Name: Urban Terror
Type: Quake3 Arena
Master Address: master://master.urbanterror.net:27950
Standard type query