Hi there! We have stayed at both the Grand Vista and Cypress Harbour. Both are great resorts, but with different feels to them.
We stayed in the Grand Vista first...our first Marriott experience and were thrilled. It has more formal decor. The Grand Vista is much newer than Cypress Harbour and thus everything inside the villa is newer. The villa we stayed in had a latex mattress on the king size bed which I had never experienced before and fell in love with...very supportive and sooooo comfortable. There were kids activities I think...we spent our time at Disney and Universal, so we didn't take advantage of anything other than the Surrey Bikes the last day. The Grand Vista had more ameneties within the villa than Cypress Harbour...dishwashing soap, lots of kitchen towels and sponge, etc., plus a laundry basket which I loved. The Grand Vista has stacked washer/dryer.
The next time we went, we stayed at Cypress Harbour. It has a calm feel to it. It was nice, but the villas were in need of a rehab (that was a few years ago so I imagine it is all done now). It is a GREAT resort when you have teenagers (which we had two on this visit). They have a great game room with teen night where they have competitions--with prizes. As I recall they had quite a few activities planned plus basketball courts and other sports things. The pool area had a volleyball net and the teens would congregate at the end of the day and play. My sons really loved it. Cypress Harbour has full size washer/dryer.
I have not stayed at our
DVC home resort yet, but just from reading the square footage and seeing photos, the Marriott villas are much, much more spacious--more like OKW. We had a dining room table that sat six at the Grand Vista and a round table that sat four at Cypress Harbour as I remember, plus the seating at the bar.
We went to visit the Marriott Horizons while we were staying at Cypress Harbour to see if it was an option the next time. (Yes, the salespeople thought it was strange that WE were asking to go on a short mini tour and not wanting anything in return. Ha!) The rooms were a bit smaller, the furniture less formal, and the pool area appeared to have a more kids oriented theme...more playful things. When we were talking to our salesperson, he said that Horizon's was being marketing to families with younger children versus Cypress Harbour is great for families with teens.
Both the Grand Vista and Cypress Harbour were quiet, set back away from any noise. We would go back to either when we are not staying at our DVC home resort. Also, Marriott has non-smoking buildings which are nice. Parking is right outside your building.
I hope this helps with some of your questions.