I just got this little J frame 351PD 22 magnum earlier this week. It's not a stainless gun, in fact it's mostly aluminum (alloy), with a steel barrel and internals. I was originally looking at the 351C hammerless, but the reports of a very heavy trigger steered me to the PD model. It's got quite a heavy trigger of it's own in DA, but the typical sweet single action that's closer to 2lbs (WAG there, have not dug out my trigger gauge yet)
I think I would also like to have a K frame 4" 22 WMR to go with it. But the airweight is perfect for carrying around the yard, now that copperheads are starting to move about. (No so much this week, we're supposed to get a freeze warning over the next night or two)
The airweights magnums are not cheap revolvers, but the stainless versions are probably twice the price. I'm not sure if the 648 even comes with a 4" barrel, but that would be my next pick. However I will be keeping this one too.