Both are fine revolvers. I prefer S&Ws double action triggers. I have had a good gunsmith do action jobs on both. When worked over the GP trigger is about as good as the S&W trigger OUT OF THE BOX. That is double action. In single action both are good.

Before S&W started making round butt grip frames on the L frames I would pay a gunsmith to RB those guns. I slightly prefer a RB L frame to the GP100 grip. In factory form I preferred the GP factory grip.

I prefer Rugers cylinder release and ejector rod design.

Overall I'm more accurate w the S&W shooting double action.

Again both revolvers are good products. I prefer the S&W but don't look down at the Ruger. Comparing a SP101 3 inch to a M60 3 inch the Ruger wins. It would be a runaway if Ruger put adjustable sights on the SP chambered in 357. That is for field carry in a belt holster. For pocket carry w a 2 inch barrel I would trade 2 Rugers for a S&W airweight Centennial or Bodyguard.