We just installed the GE Geospring as well. Until the end of the year there is a 30% federal tax credit on this particular unit which sweetened the deal. You gotta shop around for a good deal because when the tax credit was announced, they jacked up the price.
We are looking for this thing to pay for itself in a less than four years, after that, it's printin' money! :thumbsup: And I'm not necessarily "green", but I am cheap. So if it saves money, I'm all for it.
FWIW, our contractor grade A.O. Smith water heater started leaking after four years and it was a true energy hog.