The tankless question comes up here often. There are some who swear by them, but most do not. There are several negative points about them. Unless you home was designed for a tankless, you will almost certainly have a major expense getting enough power, either gas or electric. If you live in a cold climate, in the winter the incoming water is very cold and you may find the water doesn't get as hot as desired. Tankless require frequent maintenance. Tankless are more expensive than conventional heaters over the long term when every thing is considered. I would suggest you search the archives of this forum for the discussions on the topic before going tankless.