We own at HGVC Sea World, and have stayed at the one on International Drive as well. We love them both, but I'm partial to the I-drive one because I like the Italian village theming, and the fact you can walk across the street to Publix.
If you stay at the Sea World one, they have a "behind the scenes" tour thing for kids where they feed them lunch, make a craft and take a van over to Sea World and get to go behind the scenes of places like the dolphin nursery, sting ray exhibit, etc. It's been a few years ago since my 2 did it (like 3 or 4 years maybe) but it was $25 per kid and lasted about 5 hours.