I suggest you do NOT stay at Fiesta Key. It was good as a KOA when we spent three weeks there. Then it was supposed to be developed into condos. That deal fell through a few years back. Morgan has it now and the reviews say it has become a dump.
My guess is that somewhere, way out there on the back burner, there are still plans to develop condos. Until then, Morgan is not going to spend a dime on this place, and it shows.
My kids used to tent camp at the KOA in Sugarloaf. They liked the campground in general because of the facilities, plus the fact that they could get breakfast right there in the park (I assume that is still the case). I checked more current reviews. The sites are still a little small (no surprise there). And some people complained of the music noise. I guess it depends on when, and how long you intend to stay there. Three days during the week could be peaceful. A full week could be entertaining on the weekend, but maybe not so peaceful.