Anyone have one? I'm starting to get estimates, and am interested in what peoples' experience has been with them (i.e. gallons-per-minute capacity needed, installation costs, etc). I like the fact that they are energy efficient (and really like the federal tax credit), but it's mainly the unlimited hot water I'm after.
They also take up a lot less space, a nice plus for anyone not rolling in square footage. Could free up an extra closet equivalent.