We did the walking and kayaking tour. I wasn't expecting much but it was a lot of fun and very informative. They walk you into areas that you're not generally allowed to go, give you information about the history of the island and the area and the vegetation and then take you to a private area where they teach you how to kayak. Then you double up and kayak over to another beach where you spend some time and then kayak back.
The feeding and swimming with the stingrays was fun too but short. We've parasailed and I was terrified to go but it turned out not to be frightening at all. We're booked again and hopefully it will work out. We've booked it two other times but was cancelled due to high wind and waves. We also did the wave runners. I wiped us out near the end. It's not really dangerous but I didn't care too much for it - too fast and uncontrolled for my liking.