I had one. Pros were its tough design, no sideplate, is built strong. However, it will loosen with a lot of high pressure .357s, just takes a little longer than a Smith K frame. Mine was very accurate with .357. It was a very servicable, good shooting, tough gun and rather light, lighter than the GP100/S&W 686. It's more of a K frame size gun, but tougher than a K frame. The trigger on the gun slicked up very well with a lighter hammer spring and some fluff and buff. When I got through with the trigger, it was one of the slickest I've owned.
Cons, mediocre accuracy with .38 Special stuff. That's the main reason I traded it. That will vary from gun to gun I'm quite sure. No two guns will display the same accuracy preferences even within a model line. I didn't like the way the thing recoiled using hot loads, sat rather high in the hand and rotated in the hand more than many guns I've fired including my Taurus M66, the gun I've finally settled on for a .38/.357. Even might few ounces lighter Rossi M971 had less muzzle climb. The stock grip was terrible and it needs something aftermarket for a normal hand size. I put a Hogue on it and in part the recoil muzzle flip thing was probably due to that grip. However, the thing wasn't shootable with the stock grip panels, like trying to shoot a NAA mini revolver in .357.
This is how I see the gun. It's still one of my favorites for carry. Sorta wish I'd have kept mine, but I really wanted the Blackhawk I got for it, even swap. The Taurus I have now has a nice trigger and is much, much more accurate with .38 and just as accurate with .357. I'm keepin' that one, but that don't mean I might not buy a good used Security Six sometime.