I cannot tell any difference in my gas bill. Most of my customers that do alot of research go back with a tanked heater.
I don't recommend electric tankless. and are very hard to find parts for.
ya and good luck getting anyone to work on it plumbers want to make the money putting them in but wont come back to work on them, iv worked on several different brands and every customer tells me they wont (plumber) come back to work on them and for you "do it yourselfers" that think they can work on it they are a challenge to say the least until youve worked on a few...ASKING has alot of good points, iv been putting them in for over 12 years, several sonics, slaughter houses and some residential house and have one in my house, IMO, its all comes down to HOT WATER USAGE, i have a 4x6 master shower with 9 shower heads (like a human car wash) with a neo-angle whirlpool, IF you JUST HAVE TO HAVE ONE i would suggest a gas PAMOLA brand (theres a dealer in OKC) the reason is this is the only brand i have found that doesnt need electric to run (all other brands do) in other words if the electric goes out you DONT have hot water...retro-fitting will cost more (replacing a tank type) than building new (new house)...but good luck with your decision...