The zip line there is pretty new, haven't heard anything about it yet. I've done the waverunner excursion, tons of fun. The beaches are wonderful, don't just stop at the first one you see, that one is always crowded. You can walk over to the other side and there is a lot more room and you'll also fine the BBQ lunch, don't miss that.
The BBQ lunch is free and is located in 3 different spots on the beach, so don't miss it. The beach is totally gated in, so its private and not a problem.