This is a stiff boat- the floor is rock solid unlike many of Sevylor's products in the past. It handles whitewater well- Mine has been run many times down the New River Gorge in WV. It has proven to be more durable than my Tomcat- a vinyl bladder boat.
The seat on the DS sucks. I feel like I'm doing squats when I'm in this boat but the younger crowd doesn't seem to mind it as much as I do. You'll benefit from adding some straps for your legs. Its a wet ride but the boat is super maneuverable and easy to climb back into because the tube diameter is smaller than most other ducks.
Good luck finding one. They're a great value if your looking to get into whitewater on the cheap.