I have stayed there twice already, once in the bayous, once in the mansions. I am ging again in july, and am staying in the mansions.
I think both are equally nice. Some of the bayous can be out of the way, so if you are going with little kids it might be eaier to stay in the mansions because most of them are closer to everything, (busses, food, and pool)
theres alot more vegetations and shade in the bayous, and the mansions have just as much, but its different because evrey thins is landscaped as if it were a mansions.
the room sizes are exactly the same. they are jsut decorated differently!
Good luck!
Hope you have a great time!