Pros.. Inexpensive and quite safe. Max temperature is self regulating. Within a crowded camper, would hard pressed to catch alight something or seriously burn yourself.
Cons... They use electricity.
Energy only changes form. There is no free lunch.
Also they don't add moisture to the air and can be used to help dry clothes if you hang them on a line above the heater. I tried one of the small ceramic heaters in my VW camper when I had it but went back to a radiant style with the metal heating strip that I have that I liked better; it's a little larger and seemed to do a better job at the time not only keeping the van warmer but helping keep the windows from icing. I have used the small ceramic heater in the back of the truck but have to keep it turned all the way down or it gets too hot.