We did the banana boat in May. It was a lot of fun. At that time, they pulled you behind a jet ski. On our Jan trip, I noticed they were pulling you behind a boat instead of a jet ski.
Word of warning is to wear some sort of shorts to protect the inside of your thighs. You bounce up and down, and there's a lot of sand on the "banana", so you end up with an UGLY rash! Also swim goggles would be a good idea because the water splashes in your face!
My DH took the fishing charter this time. It was pricey ($110) but he caught some really great fish. The hooked into a couple of BIG sharks and everyone on the boat got to battle!
Enjoy!