I have a propane generator in my 5er. I love it for the convince of not needing another fuel source, and that the fuel doesn't go bad/I don't have to worry about carb issues.
I don't like it because it is a propane HOG. This summer, we ran it while dry camping at a lake so the dogs could stay inside in the air conditioning. I basically went through a 30 pound bottle in one day (read that as about 12 hours of run time). And swapping out propane bottles can be a pain.
As others have said, if you need something that is automatic and you already have a propane tank. that might work. Natural gas would be my first choice. But I am one that would go with gas over propane. Where I am at, it would be easy to grab a couple gas cans and head to the station a few miles down the road when the power goes out.