Over 6 years now, and the Savage heater has only needed a flow switch and a temperature switch. Like Bob says it just works. You flip the switch and go clean. NOTHING to think about. Even us dumb Kanadians can use it. I fill the 9 gallon belly tank once every 10 days or so. When you need propane you notice how common it is.
I lived in South America for 5 years and almost ALL the Taxi's run on do it yourself propane installations. It gets over 120F in the summer and I never heard of any problems. They actually use 5 gallon propane tanks (right in their house) to cook with on their propane stoves. They deliver three 5lb propane tanks on the back of mopeds secured with bungie chords. Once I saw them fall off and bounce down the highway. The guy stopped, picked them back up, put them back on and kept going.
They also use propane powered on demand water heaters mounted on their walls over the sink. Loved hearing the the sound of the propane igniting when you turn on the tap.
The problem in North America is the paranoia spread by many distributors who only sell heat exchanger machines.
If you choose propane, do it right and have a belly tank. Use a bulkhead through the van floor and get one that is fully automated. If I had to manually light mine or worry about the pilot blowing out by wind, I would go to a heat exchanger machine. I love my Savage heater, especially when I clean during our long sub zero winters.