I have a new Model 60 with the lock, and I pretty much just forget it's there. It might be handy to have, in some situations, but I've never used it aside from checking it out when I first got the gun.
This S&W revolver happens to be one of the best firearms I've owned, so I have no complaints about QC. A 3" snub that rings the gong at 50 yards as long as I do my part is a good gun. It also looks very good, and the lock is barely noticeable.