I did a voice delay test of the three most commonly used voice applications for gaming, and combined them into a video. For anyone curious, it can be viewed here: http://gcguild.net/movie/ventrilo-vs-teamspeak-vs-mumble
gc's mumble. all three were on our server, otherwise you'd get different results with latency. has gc mumble been down recently? I took it offline intentionally a couple of days ago when I upgraded the server, but that should have only been an hour or so. Demps and myself use it at times, I think some people use it for arena also.
As i have said before, the main "problem" with mumble is that it takes more of an effort to get setup correctly. After you set it up it sounds the exact same as vent, if not better.
Essentially you need to actually do the audio setup wizard when setting up the client for the first time, and not click 'next' 5 times without reading anything. Another issue with mumble is it is really lacking in administrative tools. Much more barebones than ventrilo. TS3 wins in that department.
when i logged on mumble fort he first time ever dox told me to do like 3 easy things he posted in his vent comment and mumble was working godlike fine for me its supereasy i dont know why anyone would have trouble setting theirs