I spent a short time at these properties at the beginning of September. I don't know the differences on the "Vacation Club" portion of the hotels, but I noted a few differences in the hotels themselves, among which would be that the Beach is a bit larger than the Palace and the Palace is a bit more luxurious than the Beach. The two hotels offer sharing privileges so it's not that big a deal really where you end up since you can use the facilities of both. There are more a la cartes at the Palace and the most fantastically situated buffet on the beach at the Beach. I believe you pay $10 to dine at the a la cartes at the Palace when a guest at the Beach. The Beach also has really cute bungalows, though on the inside there's not a lot of difference compared to a standard room. The beachfront ones are obviously the best! The two properties have 3 pools, with one being at the Beach. The theater is at the Beach and the disco is on the Palace side. The beach activities appear to be set up on the Palace side. There are also some shops at the Palace in a cluster, clothes and a Conchita Llach store, paintings and crafts and a logo shop.
There are very few (coming up empty remembering even one, actually) open green spaces at the properties with building on building on pool on restaurant on tennis court on cultivated pond area.
With all the good points and weaker ones, I'd return!
Kaki