The zip lines are fantastic. I hate roller coasters and have never parasailed so can't help you there except to say it is nothing like a roller coaster. It is pure speed and breaking. The higher the speed, the easier it is. That is why some light weights have problems. Breaking is all in technique (i.e., if you are on a good enough course where you can build up speed) and the amount of slack in the line.
I would definitely go for it!
