I'm not sure of the specifics of the sound system, however I do know that it sounds great...better than ventrillo or teamspeak for any of you who have ever used those. In fact, Praetor (one of the GMs) is wanting sound quality to be top notch as he is trying to pipe in music simultaneously. Eventually we would like to be able to stream music of choice as you play, or have a selection of player made Mp3s available for download depending upon the genre of your game. Anyhow, I will ask the devs more about the specifics of the sound tech.
As of yet there is no Mac capability, however we are looking into trying to implement that sometime in the future if possible.
The client is working quite well considering the gap between the players. In fact we are even testing with someone in Japan at the moment.
Yes there are both friendly and pro-GM run games, but it costs no extra to play in the friendly games. In fact we have clan pages so that groups of players may come together and use their clan page to organize games as well as chat in their own personal forums. The pro-GM games do cost more, but are well worth it, as we screen GM's thoroughly, and the experience is like no other (not to mention dungeon dives, arena championships, and tournaments).
We will be offering a free demo of sorts. I know that any pre- reg user gets a second account that lasts for one game session so that they can let a friend join up to a game and see what its like...however we want the client to be fully functional and as bugless as possible before we implement the demo. Im not sure what we have planned for other demo offers, Ill have to ask and see.
As far as what we offer, well, full voice conferencing for one, as well a dynamic community behind the client (which I believe can totally sell itself once you've tried it). The interface itself is completely skinnable, and is usable with ANY game system, not just d20. As far as I know, FG offers only d20 (although they have a great interface). We are also hiring both artists as well as writers who have worked in the RPG/fantasy/sci-fi/whatever field before. There is a ton more, but the website does a better job describing that than I ever could.
Anyhow, lemme know if ya have any more questions.
Asch