I just replaced my tankless with a regular gas hot water heater.
The tankless came with the house when we bought it. It is a 2 story with 3.5 baths. I have 2 toddler girls, and with all the dishes, clothes, baths and showers we take, the tankless was too inconsistent. Plus we had to send it in because one of the elements failed. When they sent it back with all new parts, it only worked for a 1/2 day. That was enough for me.
I think that if you bought a new one and didn't use too much water at once, they probably work OK.