I've installed tons of clutches, both stock and aftermarket at the suzuki dealership i work at and haven't personally seen any issue with either. I assume the stock clutches will last a bit longer. The main issue I've seen with aftermarket is in the springs. barnett springs tend to be stiffer than stock. I have heard people complain about barnett stuff but never experienced any problems myself. The other thing to watch out for is the number of plates, I've seen a few aftermarket kits that are very universal and might come with one too many plates OR if your inner plate is a smaller ID sometimes the a/m kit uses the same size as the outers and you're just supposed to use it without the spacer ring washer thing that was stock.