The Taurus 856 still isn't the 642, and that matters more than the price gap
I'll cut to it: yes, Taurus quality has improved. No, it hasn't improved enough to make the 856 the rational choice if you can actually afford the 642.
Look, I sell both. The 856 walks out of here regularly — usually because someone's on a hard budget or wants a backup gun and doesn't want to sink $450 into it. That's a legitimate use case. For that customer, the 856 does what it's supposed to do: it's a five-shot .38 that goes bang reliably enough. I've had fewer lemons come back than I did five years ago. Taurus fixed some real problems with their QC.
But here's where the value math breaks: the 642 has institutional reliability. S&W's j-frame has thirty-plus years of actual carry data. Holster makers design for it. Gunsmiths can tune it. If your 642 breaks — and it won't — finding parts and someone who knows them is trivial. Try that with the 856. I've had two 856 customers call asking about trigger jobs. I told them to call Taurus's warranty, because I'm not touching it and I don't know anyone locally who will.
The trigger on the 642 is also, still, noticeably better out of the box. That matters in a defensive revolver more than people admit. The 856's trigger isn't *bad* anymore, but you're pulling through sand compared to what Smith gives you.
Cost-wise, we're talking $250–300 difference depending on what's in stock. That's not huge. For a carry gun — something you're betting your life on — I'd rather spend it and own the gun everyone's been carrying since Clinton was president. I know what its problems are. I can fix them. I can recommend with confidence. When I hand someone a 642, I'm not thinking about whether the firing pin retainer's going to stay put.
The Taurus 856 is a competent gun now. I'm not running it down. But "competent" and "as good as the alternative" aren't the same thing, and in the snub-nose market, they still aren't. If budget is the real constraint, the 856 makes sense — that's not weakness talking, that's reality. But if you're trying to decide between them and money isn't the limiting factor, spend the extra and own peace of mind.