Do you find that the electric or gas versions perform better - have fewer problems?
Tankless hot water heaters are great for saving energy. Solar hot water systems and heat pump style water heaters are also pretty good these days.
Power companies hate these. Imagine every house in your city using a tankless system. Now imagine them all turning on at about 7:30am every day for morning showers. Now imagine that happening 5 days a week during the school year. Power companies are not equipped to deal with usage spikes of this magnitude. These things, as fantastic as they are, will cause far more problems for the public than they will fix.
I'd had a bad experience coming and going, and then all I wanted was a glass of red wine and they were completely out. Also, if you didn't know, it's no longer $5 per glass but $7. I joked with her about my frustration with the merger and that they were killing me here between that and the no-red-wine and ultimately said forget it to the wine. But she listened, shared some of her frustrations with me and ultimately brought me back a free glass of white wine.
That little joking exchange and freebie literally made my entire trip. I didn't care about all the other stupid inconveniences. Because of Rosemary, I may consider flying United/Continental again.
In general, the home owner will save money on their electric bill but will spend more to purchase and have it installed. While they do have their place and are great for certain applications, many home owners will never recover the costs and will actually lose money in the long run.
I can say that tankless water heaters are about the size of a briefcase they save valuable floor space that can be used for storage etc. especially in condos and apartments.