I have stayed in both Cabana and Casitas, both are great.
I prefer the Casitas with its walkways, fountains and topiaries. It has more of a old city feel.
The cabanas are great if you like a beachy feeling. There is a beach with hammocks on the Cabana side.
My mother stayed in the Rancheros and said it was like being in Arizonia, lots of cactus and rocks, but she liked it.
It is a great resort I think you will be happy with what ever you choose.