We stayed at Horizons in April. My kids loved it. There was a lot of activities for them. It is still being built, but I think most of it is suppossed to be finished by the end of the year. The pool is zero depth, and it has a big pirate ship with water canons and slides. There are two hot tub pools and a small toddler pool. Your youngest will be able to play on the pirate ship, it is in the shallow end. Your other two will also have a great time on it. Threre is a water play ground that has all kinds of sprinkler type of things and two towers that have huge buckets on top that fill with water that dump out and get you soaked. I was told that they are going to put a lazy river pool in. There is a poolside bar that serves light meals (burgers, sandwiches, salads etc...). There is a game room that has video games and an air hockey table. There is a small but decent gym.
The rooms were nice, roomy enough for my tribe. We went and looked at Grand Vista and it is beautiful. They have two and three bedrooms. The property is very nice. I can't really speak about the activities for the kids, because we didn't stay there. We are thinking about buying a timeshare, but are going to take our time and go stay at some to compare everything. Lisa P., thank you for your advice on my past posts, TUGS is a great site.
If you stay at Horizons I think you will be pleased.