I went from a traditional 6 gallon gas hot water heater in my C class to the tankless in my Precept. After learning the hot water only trick, I haven't had any problems getting the temperature right and still taking my Navy showers, especially since almost all of my camping is boondocking. During the summer, I have adjusted the water temp to about 1/8 above the lowest setting, where as during some freezing February weather, I had to adjust it much higher. My 13 year daughter had no trouble getting the hang of it, too.
And don't forget, winterizing is much easier with the tankless. It was a real pain winterizing with the 6 gallon Suburban.
2015 Jayco Precept 29UM
2014 Wells Cargo Road Force 7x12 vnose
2000 Gulfstream Conquest Sport C class Chevy 454