Curry Hammock is our favorite of the Keys SP's, mostly because of our dog - even though he is not permitted on the beaches of any of the parks, he can come sit with us on the grass at the public portion of the beach where we have an ocean view and can take a dip if the tide is high enough. It is right down the street from Coco Plum public beach, which permits dogs. It is also within easy striking distance of Marathon, with dog friendly Sombrero Beach, and lots of bars and restaurants with dog friendly outside dining, and supermarkets, home depot, etc. All the sites are decent, although very few have an ocean view due to the vegetation. Each side is dead level, drains well, and maintained beautifully. The bath house has the best showers we have seen in the Keys. Only shortcoming as we see it is there are no laundry facilities on site.
Bahia Honda waterfront sites have the best views, with Long Key a close second, but there is more road noise at these two parks. Pennecamp is pretty nice too, and has sewer, but as someone already said, it is pretty far up the keys from the areas we really like.