This is an easy one to answer. The 4” full-lug GP100, seen in my avatar image, is my favorite revolving pistol. I bought it in the very early Nineties, to be a utility/field sixgun. I was truly impressed by the fit and feel of the grip, and the natural-for-me reach to the face of the trigger. My accuracy potential, with the old-school factory grip, was (and is) as good as with a K- or L-Frame with a custom grip. In early 1993, I finally got tired of finding that my duty SIG P220 pistol’s magazine having released itself*, yet again, and used this GP100 as an interim duty handgun. Two weeks into that, I used this GP100 to fire the only line-of-duty shot of my LE career. To make a long story short, I decided to keep using DA revolvers as duty and personal carry handguns for several more years, before returning to using autos for duty and personal carry, in 1997.
My accuracy potential and consistency with a well-fitting medium/large revolver is better than with any other handgun. A GP100, with the original Eighties factory grip, is the perfect example. So, a GP100 might be my favorite revolver, regardless, but having used this GP100, in the above-described decisive moment, perhaps a life-saving moment, certainly adds to its status.
I still use revolvers, having retired from LEO-ing, and no longer fully trusting my gimpy right hand to provide a stable platform for reliable auto-pistol functioning, with all autos. I will generally use 4” and longer-barreled revolvers when away from town, and shorter weapons in town, though there is some cross-over. I have 3” to 6” GP100 revolvers. I also like Ruger Speed Six and SP101, and S&W K- and L-Frames. (We live in a small, independent city that is totally surrounded by the larger, sprawling Houston, Texas.)
*It was the old-school, “European” heel-clip mag version that was releasing, when it snagged on such things as the fabric of the patrol car’s seat cushions. The mag would not eject, because the heel clip maintained tension against the back of the mag. Even so, the top-most round, in the mag, would not have fed, with the mag in the partially-ejected state. After the fourth such incident, the P220 just had to be pulled from service. Notably, I returned to SIG, in 2004, in the form of the P229R, which became my longest-serving individual duty pistol, until 2015.