Mumble > All
WAY WAY better, auto-audio normalization, and graphics overlay so you see who is talking in game. I refuse to install Vent or TS, both of those are far inferior and just outright suck.
Edit: I know vent and TS have add-ons and settings to adjust to give some version of what I've said above, but its usually a half baked solution that doesn't work nearly as well as Mumble.