I had an early model 686, and while it will "handle" hot loads, it had to be retimed on three separate occasions, hot handloads will beat up the lockwork. So yes, the GP-100 will do better over the long run with a steady diet of hot loads. But my 686 wasn't exactly pampered, I put just over 46,000 rounds thru it in the space of five or six years, and 90% were full-house magnums. Not many guns will see that much shooting, especially with magnum loads. I was a glutton for punishment back then, and have moderated things since. The S&W's lockwork may be more delicate, but no Ruger DA revolver I've ever seen had a trigger pull anywhere near as slick and smooth as a good S&W. The price you pay for that sweet trigger is earlier wear, but only if you abuse it, like I did. These days, when I want to shoot Macho Man loads, I shoot a Ruger. When I want to enjoy my shooting or practice a lot, I shoot normal loads out of my Smith. Either will outlive my kids if properly cared for.
Papajohn