We stayed in one of the group sites and it was beautiful. Less tree cover than we would have liked, you're basically in a giant grassy field, but it was perfect for a large group. we did have to share a pavilion with a group of older campers (celebrating a 90th birthday. Our group was there to celebrate my 30th) but it turned out perfectly as they did early dinners and went to bed in their campers.
The beach is nice, a little small, but clean and fun (would be nice if your pets were allowed to swim also).
The only real negative I have is that for each group site there is a single fire pit. This made cooking, sitting around the fire, and many other things quite difficult. There IS a large charcoal grill that can be used, but if you're doing separate meals, it will be hard to coordinate.