congrats!
I am a long time OBBR owner (1996) and LOVE it there. Beautiful resort with wonderful staff. January is a hard month to get an exchange for, so you have done well. There are so many things to do and see on SXM that you can easily overload yourself. Hop on over to TTOL
http://www.traveltalkonline.com/forums/postlist.php?Cat=0&Board=stmartin to find out everything that you would ever want to know about SXM (and the FOOD!) and see what interests you.
It all depends on what you are looking for in a vacation. I love the fact that OBBR is off the beaten track (rent a car!) but others miss walking to tons of nightlife.
So in a nutshell, you can be as busy as you like or do nothing but hang out on the beach all day - there are 36 or 37 to choose from and each is different - in looks, vibe, sand texture, facilities and occupancy - something for everyone. And then top off the day with a fine meal.
We have been all over the Caribbean and found SXM to have the perfect combination of things we like.
Enjoy your trip!
LeAnn