I'm used to using Teamspeak all the time, not here but for moderating Ascentia, some active Minecarft server I work on as a general moderator. Teamspeak can look hard to use, I was confused when they implanted the new design, but it's very easy to use once you know the few basic stuff.
You can create groups of more than 100 players if you want to, it's a really cool way of communicating when organising some gaming event or for work. The only things you can't do is activate your webcam and speak face-to-face with other people, but there are services online that propose that kind of thing, or send them something from your computer. Overall, it's really cool!