I like the K-frames quite a bit... the geometry and size is perfect for my hand. As such, I tend to use a K-frame when I'm shooting a match that calls for fast shooting at closer range. If you follow such things, Jerry Miculek has set most of his revolver shooting world records with M66 revolvers, FWIW.
But the K-frame is not a robust platform. They shoot "loose" if fed a steady diet of 357 Magnum ammo over time. The M65 in my photo had to be rebuilt by S&W after I had shot it over 3 IDPA seasons. In fairness, it was a PD-surplus revolver that I bought used, and I did fire a lot of rounds through it. But still, it needed a rebuild after I put less than 30,000 rounds through it. By contrast, my 686's have 40,000+ rounds each through them, and are still running tickety-boo.
The 686 is one of the few times that a compromise worked/works. The L-frame is, IMHO, the perfect frame size for a working revolver in a serious caliber (357 Mag, 41, Mag, 44 Mag/Spl, 45 Colt). I have 3 686's, a 586, and now a Model 69 (5-shot 44 Mag) in L-frames, and they are all keepers. I plan to get more. I need to get someone to build me one in 45 Colt one of these days...
