We are on our second one as we had it installed in the current house and had one in the last house. We too never run out of hot water. It heats the water as you need not keeping hot water on standby all the times as with regular hot water heaters. Our current house had the hot water heater installed in a closet in the foyer hallway and it was fairly old. We could just imagine comeing home one day to a leaking water heater and having ruined floors. They are not cheap to install but you will save that money in heating bills. Remember, you are not heating water 24 hours a day anymore. Our only negative with it is that it takes about a minute to get hot water to the kitchen sink (fartherist point away from the heater) and if I keep turning the hot water on and off as I am washing dish after dish, it will start to run cold before going back to hot again. However, we are looking into installing the recirculting pump that will remedy that problem. In the meantime, I just make sure to wash a bunch of the dirty pots, etc. then rinse them all at once instead of one at a time so I don't have the "going cold" problem.
Forgot to say, we never run out of hot water while showering as it just continues to heat water as long as someone has the shower on.