We stayed there twice, both time early season trips where only one loop was open and not many campers around, so it was nice. Cold, but nice. I've heard they get a seedier crowd in the meat of the season, so I haven't been back. There are some great hiking trails and don't miss Hopewell Furnace if you haven't visited there. Great history!
The biggest thing we didn't like was the campground was at the top of a hill because we're bike riders, so the last thing you do every time you go on a ride is climb that darned hill on the way home. It'll test you for sure. Other than that, we liked it there, but summer may tell a different tale.