We stayed there in March 2012 for a week (thanks to a forum member who posted a heads up that he was going to canx) and enjoyed a relaxing time. Sites are white rock gravel with picnic table (and we were visited by a raccoon once while eating.). We used the coin laundry facilities and appreciated having them. There was a friendly, peaceful atmosphere in the CG, and the March weather was perfect.
We didn't use the beach (water too cold for me to swim unless it's over 85 degrees) but other people did. There is a little snorkeling apparently from the beach but the real reef is miles offshore, reached only by boat. It's a bit of a walk from the campground to the beach and visitor/watersports center, but as said earlier, you can park there. We also took one of the glass bottom boat rides out to the reef on the Spirit of Pennekamp.
There are many restaurants in Key Largo very nearby if you like to go out to dinner, and you can of course make day trips south.
It's a very different atmosphere than Long Key because the campsites face each other across the road, so less private. And of course, your site is not near the water. But it is still a fine place to stay at a great price for the location in winter time.