We've had one for about ten years and it's been pretty good. It ended up not being hugely more than a conventional system because we replaced both the furnace a

We've had one for about ten years and it's been pretty good. It ended up not being hugely more than a conventional system because we replaced both the furnace and the water heater with one unit. The installation was not cheap, though. The biggest advantage for us was that it's small, and the space in our basement is cramped and prone to taking in water. So being able to have it well off the floor was plus. The main thing to worry about is making sure you get an installer that knows the system and can do maintenance.