We have stayed in all three.
Ranchos is our favorite. Why? Close to the main pool which is very self contained with quick service, mug refill, playground all right there plus it's a great pool with lots of lounges and tables. Ranchos is the most creative, highly imagineered section of the resort and across other resorts as well - looking nothing like where we live so feels exotic. Close to our bus stop. Lovely empty quiet pool. A beautiful walk to the main hub that never took more than 5-6 minutes unless we stopped to look at flowers and wildlife.
Cabanas is second. It's a beautiful space with beaches and a tropical feel. The buildings are more plain but that fits the theme. Huge plus is the location to main hub. Has business class rooms and would gladly book them again, they can be a huge perk.
Casitas our least. They are tall and feel like Florida condominium buildings throughout. Nothing special here. Close to main/convention hub and we see lots of the business folks staying here. The quiet pool is by the fitness center/spa and always seems to be crowded. Plus is first bus stop and MAYBE short walk to hub; some of the far buildings have as long as walk as other sections farthest rooms.