I was issued a Model 15 when I first started at the Sheriff's office many, many years ago. It had been used and abused, but it had the sweetest action of any revolver I ever shot. These were the 4" blued versions and it served me well for several years until we switched to the stainless Model 66's. The 66's were nice and we were given a choice of the 4" or 6" for patrol and the 2-1/2" version for plainclothes work, but they never had the smooth actions like the old Model 15's did. The 66's were also chambered in .357 magnum, but all we were allowed to carry were .38spl's.
In the civilian world, the Model 15 came in either a blue or nickel finish and you also had the choice of a 2" or 4" barrel. The stainless version is the model 67 and that only came in the 4" barrel if I remember correctly.
I have the Model 18, which is the .22 version and it is a great trail gun. You can't go wrong with the Model 15. They are running anywhere from $350 to $450 depending on condition.