While I'm a real S&W fan, the Ruger Security Six, especially in the 4.0 inch barrel length is my absolute favorite center fire, medium bore revolver. I have two of them, a "pre-warning" series 150 (blued steel), and a series 151 (stainless steel) that was a former Puerto Rican "state" police turn in. No, their trigger pull is not as smooth as that on a S&W, but they are well built and reliable. Oddly, few people seem to realize that the speed loaders and holsters for a S&W K-frame also work on the Ruger Security Six revolvers.
Also, probably an apocryphal tale, but an old shooting buddy that allegedly had friends with Ruger's executive management team once told me that the "GP" in the GP-100's name stood for "Great, profit" which was what Bill Ruger was alleged to have said when he learned he would actually be able to make profit from the sale of this revolver, rather than the barely-break-even sales of the Security Six line of products. I always thought that if that story wasn't true, it was one that ought to be.
Regards,
Dave