for us maybe not sooo important since we have the B3 (and a plan for a similar interface basing on b3)
It has great rcon capabilities, theres nothing comparable.
Xfire is a noobi progi, compared with HLSW.
HLSW (http://www.hlsw.org) is working now with Urban Terror.
U can use this tool to have ur personal favorites lists from windoof, watching whos playing where.
theres some fancy features like chat etc, but those features are way behind Xfire.
HLSWs strenght is the rcon.
Anyways, its worth a look for any player.
Its working with allmost all mods of Halflife 1/2 (HSLW = Half Life Server Watch) and Quake3.
Ah:
cheeeeeeeese! klick.
the HLSW traceroute tool is the most advanced of its kind (at least idk any comparable), its the reason why i install it on any windoof serwer: