We go there at about 1-2 times a year, but we pick the times when rates are lower and the weather is cooler. We recently looked at going during spring break, but the nightly rate would have ended up being at least $180 per night, so we picked a hotel instead. The difference is that we live 2 hours away, so we can do 2 parks and a single hotel night but for camping, to do 2 parks (2 days) you really need to be at the Fort for 3 nights.
I've always thought of the Fort as a convenient place to stay in your camper, but never a place to go camping. The sites can be challenging to get into sometimes, and we've had some run-ins with careless and reckless attitudes of drivers who want too drive waaaaayyyyy too fast. However, we've gemerally had positive experiences. One thing we've decided not to do again is going there without going to the parks. We got pretty bored of just hanging around the campground all day, because there's really nothing to do there.
I do find it ironic when people who drive $60K plus trucks, pulling $30K-$50K (or more) rigs from several hours away write off the Fort due to the high prices. Like having a beach-front house and complaining about the cost of insurance...