Tankless Water Heater Q?

I had a similar experience as Boutros--after we had a bit of trouble with our current water heater and the plumber mentioned that it's starting to show its age, I talked to the tankless specialist he recommended. And that guy talked me out of it, citing the same reasons Boutros mentions. He said that the tankless is worth doing in a new house or in a major redo, but didn't recommend it for an older house.