I'm a couple of days late on this topic, but I spent about 15 minutes talking to a plumber about these systems today. It sounds like a really interesting system. It is supposed to be a really energy efficient system. The plumber thinks that the energy savings should balance out the higher up front costs in about 4 years (maybe quicker if oil prices keep going up).

Just thought I'd throw that into the conversation. Take it with a grain of salt, the guy that I was talking to sells and installs the systems and would obviously like me to talk them up and put them in other houses.