We have stayed twice at Old Key West. The resort was built for the vacation club members, but they do allow you to book rooms as well. You basically have a very nice two bedroom apartment. The master is very large with a jetted tub, the 2nd bedroom has two full sized beds and a bathroom of it's own. The nice thing about these rooms are that you have a full kitchen, so you can have breakfast in your room, another great perk is washer and dryer in your room!!
There is a large main pool and smaller pools sprinkled over the property.
We probably would not stay anywhere else, we've just gotten too spoiled!!
Don't dismiss the other parks, they all have something great to offer.