We tend to like the Marriotts and Cypress Harbour is our favorite. The villas there are nicer than those at Harbour Lake but they have more traditional water features as compared with Harbour Lake's pirate ship feature.
We were at Vistana Villages in December and liked it. I think that the resort was close to the Marriotts in terms of comfort and amenities and I thought that these villas were also nicer than those at Harbour Lake. Your children would probably like the ship feature at the St. Augustine (newest phase at the resort) section's pool area. We'd go back there again if none of our favorite Marriotts were available.
Grande Vista has a nice children's pool area at the new(ish) Copa Loca pool area in its West Village. I don't think it has the 'wow' factor that the Harbour Lake water features have but it's nice for the little ones. Villas are also nicer, IMO, at this resort than at Harbour Lake. Two main pool areas and two smaller, quiet pool areas located for convenient use by folks staying further away from the main pools at this big resort. Copa Loca bar and grille on the west side, Marketplace store and some other food options behind the reservations clubhouse and a sit-down restaurant above the golf course clubhouse building.
We've stayed at Sabal Palms but not the nearby Royal Palms resort. Nice villas at Sabal so I assume pretty much the same at Royal but these older Marriott resorts aren't quite as nice as Cypress Harbour, Grande Vista or the new Lakeshore Reserve. Sabal, Royal and Imperial Palm Vilas share facilities and the children's activities program is spread out between them. What this resort has is location - off SR 536 that goes right onto Disney property and close by an I-4 entrance to get to Universal.
You meant outdoor hot tubs as a requirement, right? I don't think there are indoor jacuzzis at Harbour Lake, might be wrong but I don't remember seeing them there. It seems to me that they have the big soaking tubs but not jacuzzis. Cypress Harbour and Vistana Villages have jacuzzis. I can't remember if Grande Vista has them or the big soaking tubs - maybe they have some of each.
Cypress Harbour (across the street from Harbour Lake) and Grande Vista are in the SeaWorld neighborhood, Vistana Villages is just a bit down International Drive from Grande Vista.
If you're comfortable with the Marriott timeshare family I'd suggest either staying with Harbour Lake or going with Grande Vista or Cypress Harbour for an upgrade in the villa but understand that the cool pirate ship water feature isn't at either of those resorts. If you're adventurous, go with Vistana Villages - a nicer villa plus the new ship water feature might do the trick for the children.
Dick Taylor
