We've stayed at Rivers End before. It was a nice enough campground, VERY tight though. The best part was the proximity to Tybee and The Breakfast Club restaurant!
Most recently we stayed at Red Gate. Its a small campground, not much amenities that I recall (we stay in February though). It was clean, no real "Bathhouse" per se, but they had 2 full bathrooms in the office that were open 24 hours a day. Its located on a nice piece of property and was a nice place to walk around with the kids and dogs.
We've also stayed at Savannah Oaks before. That was a year that we didn't make reservations and everything else was booked. Savannah Oaks had worse reviews, but we loved it. Lots of Spanish Moss trees, big sites, clean bathhouse, relatively close to the city.
Granted, when we go to Savannah we essentially use our RV as a hotel room, so we weren't hanging out at the campground other than breakfast, dinner and sleeping.