Qutecom is a very fine VoIP client running on Windows/Mac/Linux already. Itâ€™s the official successor of Wengophone. Has anyone gotten around to trying to port it already? Unfortunately, I donâ€™t know enough of C++ to do it myself. :/
It's more about how rather than what. Presence, IM, voice, and video are possible with both protocols, but each has a different slant on how those functions work which makes neither protocol ideal for all environments.