I'm a firm believer that the Security/Service/Speed Six guns are one of the bigger unsung/underpriced bargains to be had out there-I much prefer them to their Smith & Wesson and Colt contemporarys. Since over 1.2 million of them were made, you'd expect to see more available-bit apparently those of us who have 'em have realized just how good they are, so there aren't normally a lot of them available at any given time on the secondary market. As Jerry Kuhnhausen commented in his manual on them, there normally just isn't much that goes wrong with a -Six double action revolver (and you never have to worry about a cylinder crane screw loosening at the most unopportune time either).
On mine (a 1978-vintage stainless steel .357 magnum standard barrel model), I added the Millett Orange-Bar front sight; it came (fortuitously) with Ruger's plain black wide notch rear sight, so I kept that. Mine came with the optional wood Ruger target grips, which weren't exactly on the cutting edge of ergonomics or speed-loader user friendliness, so after experimenting with a Hogue rubber grip (as in the Security Six pictured in the response just above), I ended up with a set of Trausch TJ84R grips modified for me by Jacques Trausch (he cut the grip butt to fit the square-butt Security Six, and cut down the left grip's thumb ridge to facilitate unhindered ejection and speedloader insertion). I really like the enclosed backstrap and beavertail of the Trausch grips, along with their superb ergonomics and pointability.
Mine is used for IDPA, carry, steel plate competition, and home nightstand duty. I had Blade-Tech make a kydex IWB holster for it, and use a Bianchi Accumold double speedloader pouch (supplimented by individual Uncle Mike's single speedloader pouches as necessary), and also use Bianchi Speedloader strips contained in a upsidedown Galco 2 X 2 X 2 case for concealed carry purposes). For field use, I also have a Bianchi UM84R flap holster, and a vintage Hunter leather holster. Truth be told, I actually find that I prefer the Security Six to my extensively customized Chris Peters GP100...a magnificent gun in its own right.
I have my sights zero'd for 125gr +P loads; for carry, I prefer Remington 125gr +P Golden Sabers, and for matches whatever corresponding 125+P ammunition I can get my hands on-frequently Remington/UMC SJHP, Blazer Aluminum SJHP, or Winchester jacketed ball.
They're a great contemporary classic, and extremely usable, combat revolver.
Best, Jon