I have two small electric heaters with fans. One was fairly expensive (maybe $120?) only because I bought it at West Marine and it was designed for use in boats as it has an Anti-Freeze setting. Basically you leave it plugged in in your stored boat or motorhome (if you're hooked to power) and the heater kicks on if the temperature drops below 40 degrees. Keeps things from freezing while at the same time not costing you a fortune running all the time.
Anyway, the thing I was going to say is efficiency is really relevant most of the time as generally when you are using an electric heater in a motorhome you have already paid a flat rate that includes power. So when I'm in a full hook up site I use only the electric heaters. When I'm footing the bill I use my propane heaters. I like the electric heat better as the propane heat seems to cause too much of a stuffy type feeling.