My daughter and I recently took the 1-hour horseback riding tour. As others noted, the approach to the area is a bit underwhelming, as you do drive through a petroleum plant. However, once you arrive you will find the staff friendly and welcoming.
Our 1 hour ride took us up over the ridge for some very nice views of the bay where the nature center sits, as well as the next bay over. The views were very nice. Our guide (Abby?) was very friendly and shared interesting tidbits on the area. As it was just my daughter and I, it was a very personal focused excursion which was great! The ride ended with the best part...taking the horses into the ocean! We both really enjoyed that portion of the ride - but just to make sure other readers are aware, that is really only maybe 5 minutes of the whole ride.
I'd recommend it to other visitors to St. Maarten looking for an interesting way to see other parts of the island when you have gotten your fill of beaches and shopping!