I run a Mumble VOIP server, have tested Teamspeak before i shifted to mumble. I don't generally use it only for Gaming, but i prefer it for normal Push-to-Talk conversations. Mumble VOIP has a server- Murmur, it's simple to setup via Command line and you're ready to go. It also has clients for mobile devices, thus i love using it as a Push-to-talk application. It has a very low latency and is best for lower bandwidth networks. Have you setup a VOIP server?