I love these firearms. They're about the best deal going in handguns today. Of those I've owned:
Colt Police Positive Special: Light in the hand, exceedingly accurate. Somewhat funky trigger pull like all Colts. Strange backwards innards that are hard to repair, at least before the Mk III era version. Underrated.
Colt OP: A little bigger than the PPS and better known. Very accurate. Mine had a trigger somewhat stiffer than the PPS. Get them while you still can.
Colt .357. This is the ancestor of the Python but is often sold at Trooper prices for those who don't know better. It's a pleasure to shoot. Mine unfortunately had bad timing, though in hindisght I probably should have gotten it fixed and kept it.
Colt Trooper Mk. III. Nice magnum, but a bit on the heavy side. They used to go for the same price as M27's, but these days the sticker is headed north.
S&W 10: Solid and dependable. Easier to repair than a Colt. Many variations. Heavier than a PPS.
S&W 13: Sweet K-Frame magnum. A little hard to control with the high end loads.
S&W 19: The Combat. Awesome revolver, but the adjustable sights kept getting snagged on the draw. Overall I liked the 13 better.
S&W 28: A more realistic version of the 27. I found the frame too large and clunky, though.
Ruger Security Six: A real sleeper and my overall favorite of the magnums. It's slightly beefier than a K frame but not as clunky as the NT frame. It was originally sold as the slightly less expensive patrolman's sidearm to compete with the Smiths.