The RM360 in my B1700RGH can get the drinks
more than cold enough on any of the three heat sources (propane, 12V power, 120 power) if the ambient temperature is not too high. I put thermometers in both compartments, and saw it running as less than full-cold thermostat setting with -18 C in the freezer and +4 C in the 'fridge - both essentially ideal. A
refrigerator just moves heat from inside to outside, so it is limited by the
difference in the inside and outside temperatures, not just the temperature in the refrigerator (or its freezer compartment).
I made ice rapidly and had to adjust the thermostat to avoid freezing the milk while in the driveway, even on 120 VAC power, then two days later could barely maintain safe food temperatures even on
propane, because it was 27 degrees C outside where we were camping. This became a real issue for me while towing, with 12 VDC power, full sun on the trailer, and more important stuff than soft drinks and beer in the refrigerator (although of course we had those too!). Opening the door makes it worse, of course, and I think this effect is even more important than at home, because the volume of the refrigerator is so small.
I, too, find
performance (rate of cooling, or lowest temperature reached) best on
propane and worst on 12 VDC power. The three heat sources (propane burner and two separate
electrical resistance elements) all heat the same part of the system, but don't deliver the same amount of heat.
I don't have a comparison standard for newer or different RV refrigerators, but I notice that we expect them to work in surrounding temperature conditions much warmer than it ever gets in my kitchen at home, so the
Boler unit has a harder job than the one at home.
I have done nothing to my RM360 except clean the
propane burner orifice and clean the interior, and I doubt (judging from the rest of the trailer) that anything significant had been done in the past, but I really don't know.