I don't know where to start... Every RV we have had has always had a generator and I can't imagine not having one. There is little or no maintenance. I have it serviced once a year at a cost of $32. Living here in Florida, I look at my RV as a second home on wheels in case of a weather emergency. One time last year we were without electric for a day. I just got the RV, started the gen and put food in the frig and slept in it.
Although some don't approve, I sometime run the generator while traveling in the south so I can run the AC. Even if not running while traveling, it is great turning it on when you stop for lunch so that you can warm something up in the microwave.
Lots of reasons to have one.