Michael, your long term success will really depend on the quality/hardness of your water. There are small capillary tubes inside the heater that will VERY easily plug up in a short amount of time.
Because our water is so horrid in this part of SW Ontario, the local utility did extended testing, and has recommended against them. The other drawback, is reports of decreased water pressure.
As a side note, the unit you linked to was ventless and designed for installation outdoors. I would think you need to find a vented indoor unit.
