I usually research the campgrounds pretty well before I make reservations, but occasionally you can get surprised. The "resort fees" that I've encountered are usually per person and usually cover something extra... "free" breakfast, small waterpark or other activities.
If we are getting some value out of it, I usually don't mind it, especially now that I have kids who are old enough to enjoy those activities. However, if its just an overnight stop on the way to a destination, I'm usually looking for a clean, no frills park that is convenient to my route. I'll pay a couple dollars more for a cleaner/safer park, but not exorbitantly so.