The Condado Plaza is very nice, also, though more "hotel-like" than the Marriott. The Stella Solaris is more "resort-like".
We've eaten at some of the restuarants in the Condado Plaza on various occasions. If your friends like seafood the Cobia restaurant there is excellent. Their sea bass is some of the best I've ever eaten anywhere.
There are four or five others there on the second floor, also.