I just saw them for the first time at the show in Chicago last week. This is a very sophisticated platform for high-volume market makers etc. They compete directly with RTS, Orc, and Pro Opticus. As I understand it you can't use this to trade over the internet, you must be connected directly to a backbone. If I recall correctly, the cost is some $1500/month. So I believe it's only worth considering if you are a high-volume institutional trader.