We've stayed at two of those - HIFS and Marriott O. World Center. They are like apples and oranges but both great in their own way. Personally, I was "wowed" by the MOWC -- huge with a cascading water fall and a slide; luxurious and never felt crowded. HIFS is much more like a water park pool to appeal to younger kids. Fun with squirty animals, floats to rent, and TONS of babies and toddlers in the zero depth area. Definitely felt crowded at times, though, and as mentioned before, no slide. That said, our next trip includes HIFS because for the age of our kids, FUN rules over luxury.