I bought a new 686 about 7 years ago. At the time I was new to revolvers and didn't give the slightest thought to the gun having a lock. In fact, the issue of the lock never crossed my mind until I began visiting this forum. During the 6+ years that I owned the gun I put about a billion rounds downrange with it (only a slight exaggeration) without any mechanical problem, not with the lock or with anything else. It was one of the most accurate and reliable handguns I've ever owned and it was comfortable to shoot even with the hottest magnum rounds. I sold it only because I've become an N-frame fan recently and I just have too many magnums.

I'd add that I have no concerns at all about lock-equipped guns. One of my current faves is my lock-equipped 625JM.