This. I picked a 442 because I'd found sights on stainless guns hard to see in bright light. The 442 sights were easy to see, but I found that carrying it in the high humidity summers would bring rust specks on the yoke overnight if I didn't wipe it down with a silicone cloth at the end of every day. (Never on the cylinder or ejector rod, both of which were also steel - just the yoke, inside, on the surface that sat against the frame when closed.)

I subsequently acquired some stainless models (638, 640 and 632) and have carried them for years without daily maintenance, and have not a speck of rust on any of 'em. I fixed the stainless sight problem by painting the front ramp red and use a toothpick to spread flat black model paint in the cutout and face of the rear notch. The sights are even easier to see than the stock ones on the 442.

So if you're going to pick up a new one some time, I'd recommend the 642. And without the lock, if you can get one.