I just wanted to give a review of the Bosch Aquastar 125vp tankless heater, which is a propane model. I installed this unit in my home in 1987 and it is still working flawlessly today, in 2013. Yep, that's 26 years. Try doing that with any tank heater. And maintenance? Even though they recommend flushing the coil every year or so and replacing some parts periodically, I did a flush one time in 26 years and even then, it didn't really look like it needed it. I had a the diaphragm and a few other parts replaced in a one-time preventative maintenance at a cost of about $400 (and that's parts and labor). That was probably 10 years ago. This is even more amazing since I am on well water, although I do have a water softener installed. Other than the one preventative maintenance, we have had no issues with the heater. Needless to say, I have been very pleased with the Bosch Aquastar name. I would highly recommend tankess, but it's not for everyone and you need to understand its limitations and be willing to work within those. The model I have will only heat one shower at a time. You can get bigger models, but since we only have a 2-person household, this worked for us. If you have a large family, however, with several people typically showering at the same time, I doubt you would be happy with a tankless. The only other quirk is you need to understand how the unit senses when it needs to turn the burner on or off. First, you need to make sure you have a certain minimum water flow. So if you have a lower-flow shower head, for instance, you may need to boost the flow so the unit doesn't turn itself off leaving you in cold water. We accommodate this by turning on the vanity faucet to a 1/4" stream when using the low-flow shower. Problem solved. Next, you don't want to quickly adjust the hot water flow downward or, again, you risk an unexpected cold blast. Small, slow adjustments work best, keeping in mind that there must always be sufficient hot water demand through the unit to keep it from turning off. This may even mean turning DOWN the temperature at which you set your unit so that you have to increase ow much you open the hot water valves at your faucets. You just need to be patient and learn what works for your unit.