Teo has 2 different platforms, a mini-server that supports to about 150 users, a larger server scaling to 2,500 users all in one box. On-premise, hosted or hybrid options available. It looks like a solid solution that has some big security features.
I spoke with Frank at a recent conference as they are supporting their Canadian distributor, Capella, to bring their VOIP solution into Canada. Looks like a great opportunity for the channel. With demanding clients like the US Government, it should motivate the channel to sell. Ask them about their partner compensation as I think it is crazy big.