Well, here is a review from someone who actually owns one.
We have a Precision Temp RV500. For the most part, it works very well. We have found that although it uses a lot of propane while running, overall it uaes less than a tank style unit running just on propane.
There are some things that one has to get used to. They are very sensitive to the temperature of the incoming water. They will only heat the water so much and if the incoming water is very cold then the hot water output will be cooler. They are also flow dependent. So if you are in a place where water pressure is low, then the performance will suffer a bit.
Over all, we are happy with our unit.
Keith
