I have no personal experience with the scupper-type carts, but i have seen more than a few reports on various forums of damaged/leaking scuppers as a result of using this type of cart. The scuppers are the weakest part of your kayak, so why would you want to subject them to repeated wear and shock? A standard cart would probably be better.
BTW; there are at least two AKFF members who have launched with the scupper carts still installed. They couldn't figure out where all the drag was coming from until they got back to the ramp.
