We spent a week at the Marriott (not Ren) in Curacao a couple of years ago in the fall. Some pluses and minuses if you're looking for a Caribbean holiday in the fall:

Pluses: 1) There's more of a mix of cultures there than Aruba, which sometimes like an outpost of the US (which of course, some people might like for its familiarity). In Curacao, there's a mix of North American, Latino and Dutch tourists and residents and I found that it made the food and environment more interesting. 2) The diving was quite good and quite easy. There's a good diveshop on location and we were comfortable with the safety-conscious operator. We charged our daily dives through our room and got lots of MR points. 3) Decent beach, nice smallish pool and decent food (especially in the bar, surprisingly). 4) It would be a good place to kick back and relax for a week. 5) Our oceanfront room (complimentary upgrade) was comfortable and in good condition (but nothing special). 6) Curacao doesn't have the feeling you get in some tropical getaways that the hotels are rich enclaves and everyone and everything around you is impoverished. 7) It was relatively easy to get to from NYC (on AA, via Miami) with flights arriving and leaving at civilized times.

Minuses: 1) Not a lot to shop for and not a lot of non-beach activities. We rented a car one day and drove around the island. The ostrich farm was fun and we tasted Curacao liqueur. That was about it. 2) Probably one of the reasons Curacao doesn't have such a sharp rich/poor divide is because there is industry on the island (oil processing, I think). So the scenery and views are sometimes interrupted by some rather hideous processing plants.

We definitely would go back again for the diving and if we just wanted to kick back and relax. We wouldn't choose it if we wanted a more active vacation.