I have a couple of 642's, and a couple of other J frames. I've had a bunch of J frames over the years, lock and no lock versions. Never had any trouble with the lock versions, and never understood all the crying. I did have a couple of new, no lock 940's that neither made past the first 200 rounds, and when they quit working, I had to take them apart to get the remaining loaded rounds out, so they all can be a problem when they want to be.
The J frames are OK, and I shoot them on a regular basis, with hot reloads mostly, to stay on top of them, but I have a bunch of other things I feel better with. There are more than a few good autos out there these days that are about the same size as them, and you get better performance, a longer barrel, higher capacity, and faster, easier to carry reloads, and they are usually easier to shoot well with to boot. About the only thing the Airweights have going for them is their weight.
My SIG P239 in 357SIG gives me 7-8 rounds of 357MAg performance in a gun about the size as a 2" J frame (it is heavier). It has another 1.5" of barrel length and is easier to shoot than the Airweights, or even the heavier 60's using .38's. My P245 in .45acp offers the same thing.