Update: Having the Suburban tankless now for just less than three months and we are still as happy as we were on Day 1. The unit has performed well.
Since installation, we have been in six different RV Parks (in as many states) and each park has its own water situation. In some, we share a hose bib with up to four campers, in other parks the hose bib services just our coach but the pressure was quite low. No matter. The On-Demand System performs well.
Secondary to the performance is the noise level. This unit is very very quiet. We hear our neighbors' water heater firing up but ours is much quieter than the six-gallon unit we had prior.
As another has said, I share our experience, which is very positive, to encourage others thinking along this line. For us, again full-timers, we rate this as an upgrade that was worth the investment. We have also upgraded our fridge, oven, flooring, and couch.
This may only be 19' but it is our home and want to be very comfortable in it.