BOTH are beautiful resorts with excellent (similar) inroom amenities, furnishings and staff. You cannot go wrong with either of these resorts. They are located a few blocks apart and both are secluded from the main traffic streets by nice long entry roads, with 24 hour manned security gates. Here are a couple differences - fairly minor really.
Cypress Harbour:
- all 2-BR's, identical units
- older but very well-maintained
- gorgeous, lush, mature landscaping, nice & shady
- old Florida style buildings (like Disney's Old Key West)
- more fast food onsite (TCBY, Pizza Hut, deli)
- more family resort amenities, extra playgrounds, larger recreation center, etc.
- larger lake, with better marina, fun boat ride across
- attracts families, larger resort
Grande Vista:
- every unit size from studio (for 4) to 3-BR (for 12)
- is and feels newer, Spanish influence to exteriors
- nice landscaping, just not as mature & more sunny
- main pool has spouting fountain paly area for children
- deli near pool, plus sitdown casual dining at Nick's
- nice golf views, reportedly excellent golf onsite
- slightly more sophisticated atmosphere, attracting more adults
There's more similarity than difference between them though and their quality is similar - excellent. I have never known of anyone to have a bad vacation at either. So have fun!!!