When compared to TS2 it's far better, so I'll compare it to Vent.
-The latency is far better than Ventrilo, many times I have been surprised by people answering the second I ask a question, though I'm not sure if that's TS3 or just because the server THN use is a damned good one
-Sound quality is on par with Ventrilo, and when lag spikes occur it seems instead of bunching up the sound then blasting it at you in one lump when it stops like vent does, it drops the codec quality so it can continue being streamed (though it seems to eat bandwidth more than vent does so this occurs more than the bunching).
-As far as the UI and settings go, much easier to get a hold of the basic stuff compared to Vent's setup, though I still haven't found where you disable those damned pokes from popping up.
On the subject of Mumble, I already need 3 different voice comm apps installed, I don't want a to need 4th