We stayed in Casitas 4 (lagoon view). I can't speak for any of the other areas.
It was a short walk to the central area, close to one of the bus stops and not far from the pool.
It was nice and we liked it. But if I stayed there again I might be more tempted to try the area off to the right of the main lobby area.
When we were there, I was getting the impression that was the area they were lodging the convetion people.
I would either stay in that area (although the theming I liked the least) or by the main pool.
Casitas 3 was very pretty too, with the fountains and all.
Except the area opposite the main area (across the lagoon) I don't think you could do bad.
Have fun!