Jekyll Island Campground is a wonderful park with many pros and cons. There are FHU, 50 amp, pull-thru sites with plenty of room to very tight, hard to get in back-in sites. The better sites are booked up way out, so you have to plan well in advance. Also, there are the mosquitos and sand gnats that do love that area. They're not as bad during the winter months. 

The island provides plenty of activities, attractions and good restaurants (Driftwood Bistro). The island is a bicyclers heaven with miles of bike/walking trails over the whole island. The beaches are beautiful and not crowded. Check out Driftwood Beach.

There are also places to explore off the island, but you do have to pay a daily parking fee each time you enter the island. I would only buy the multi-day pass if you plan on leaving the island and returning everyday of your stay. I would recommend visiting St. Simons Island.