I've only ever been to Jamaica, and that was so long ago that nothing I know would be relevant. But for me I go on 2 types of vacations:
1) I'm exhausted from work or a wedding or something, and want to lie around, sleep, stumble to the beach and lie around some more, and let someone else cook and clean for a week. In this case I'd focus on the specific resort, and the food, and choose an all inclusive. This was how my Jamaica trip was and it was great.
2) I'm looking to see new things, and learn new things -- we went to Puerto Vallarta (not Carribbean, but I've never had this kind of vacation in the Carribbean) a few years ago and went horseback riding, and swimming with Dolphins, and looking at the local architecture, going to local art galleries etc . . . We also spent some time on the beach, and tried out some new things like boogie boarding etc . . . We stayed at a little inn where most of the other people were Mexican, and we had to walk a couple of blocks to the beach, which was fine, it meant more chances to see things and soak up the culture. Great trip.
Which are you looking for? Something in between?