I've stayed at both of these places and loved them both.
The Marriott is indeed a 4 star hotel. It is the epitome of class and you will know it staying there. On the other hand the HiFS is a FUN hotel. It offers more space and lots more to do and is way more kid friendly.
When we stayed there we could see the Marriott from the walkway to the free breakfast buffet and I remember my then 8yo son saying "Hey, Mom, remember when the Marriott was my favorite hotel?"
Will all four adults be staying together in the same room at the Marriott? I certainly hope not because the rooms are average size. If you get a Residential Suite at the HIFS it will accommodate all of you.
Whichever you choose you will enjoy them both.