I installed the Geospring this weekend, and am very pleased thus far. Very easy installation with very good instructions. Ran it the first day in hybrid mode just to see what happened, and it made enough hot water for a nice shower within just a few minutes (exactly like a regular HW tank). Been in heat pump only mode since Sunday and with just two of us here it hardly breaks a sweat. My wife reports that after one load of laundry on sanitize setting, a long shower each, and running the dishwasher on "turbo" mode, the sink water was less hot than normal but usable, so that's a pretty good test for heat pump only, and close to our max use in a day. We'll switch to hybrid mode when guests arrive over Christmas for a few days, and see if that's sufficient (65 gallons first hour recovery). If I had a larger family (especially teens) I would consider an 80 gallon, which I think they make.
No louder than a typical small dehumidifier, and the exhaust air is not very cold (feels like a small fan moving room temp air) nor coming out at anything more than velocity of a small fan running on low-med. I cannot hear the unit from around the corner in the basement, and my wife's desk is on the opposite wall from the unit, with a ventilation grid in the wall. No complaints!
No idea as to energy savings yet but will report back as bills come in. Went from 80 gallon tank previous owners had to a 50, so immediate savings there. But expect this little jewel to pay for itself in under two years, easily. Surprisingly, GE based their stated figures based on running in hybrid mode with a 135F setting. We are running at 120F (the default setting from factory, and plenty hot) and heat pump only, so should save even more than the projected $352/year.
As for automation, a $20 interface is available for hackers. I will order in next week or so and post link. Must teach myself javascript to interface, which is planned for later this month as business slows down a bit. Plan to interface with ISY or Homeseer, and both track "on" time and allow us to set to hybrid mode from Insteon keypad (and remind us to turn that off when guests leave). More info in a few weeks...