This place is a great spot for rentals. They have parasailing, paddle boarding, and waverunners. They only got a very good review from us for two reasons--one, the beach is not ideal for young renters, and they have minimal parking.
Staff were friendly, and rates seemed pretty reasonable; the shop is close to lots of restaurants and attractions on Captiva, so it's worth a drive from Sanibel. The paddle boards are their own product and kind of a hollow plastic kind related to the sit-on-top kayaks, good for beginners.
They did not offer any instruction on paddle boarding. They get four stars from us because the beach was not as good for younger kids--we took a six-year old, eight-year old, and ten-year old, and the surf was very tricky to navigate just because of how the beach was structured. If you have young kids, and they want to try paddleboarding, I would go for an area that has calmer water.
They had a blast on the waverunner, though, and overall the shop is nice and a lot of fun.
Lastly, there is minimal parking; there are three spots in front and otherwise you have to shoehorn yourself into the back lot. They do help move cars and the situation at Yolo is certainly not unique on Captiva--if you're going, you're welcome to park in back if renting.
Overall, if you're aware of these small drawbacks, you should have a great time with their rentals. We did not try parasailing, but it looked fun (if expensive).