I am already leaning towards abondoning Vent for TS3. The improvement over TS2 is amazing, and there are a few codecs on TS3 that have identical (slightly worse for some, slightly better for some others) sound quality to the Ventrilo GSM codec. There is also less lag between speaking and other people heating it compared to vent. TS3 also has a 3D sound feautre similar to mumble (Random Fact: Vent was the first system to try a 3D sound thing, but it isn't very easy to use and doesn't work quite correctly) allowing you to position where certain users sound like they are speaking from. With the clever people we have at BI, I could imagine that TS could be customised to work with surround-sound-positioning ingame like there has been done for Mumble.
There have only been two issues I've had with TS3 so far, one being that I can't use my left windows key as a PTT button (You also can't disable the PTT button so it only works in TS, from what I've seen), and the admin controls are awfy complex. Both of these issues are minor, and the majority of people will NEVER have to use the admin controls so there is really little problems here.
Even some of the "grumpier" FSers, who are stuck in their ways and were unwilling to try out TS3 just because they are used to vent are liking it (after me disabling all talking, channel switching and the ability to view other users in Vent3 that is, forcing them to at least try TS), so it's looking incredibly likely that I will be cancelling the contract I have for vent within the week. However, before I do that I *would* like the opinion of others because I will keep the Vent server up if a large group doesn't wish to switch, but before you say you don't want to switch you must at least give TS a try.
And now the top-jobs can't say that I didn't choose mumble just because I was used to vent. There were reasons, and I stated them!