All of those are fine choices. If you want the flexibility to handle .357 rounds, eliminate the model 10.

I’ve yet to meet a person who dislikes their Model 19 or 66 (They’re essentially the same gun, 19 is usually blued, 66 is stainless). K frame is a great size, adjustable sights, .357 mag flexibility… what’s not to love?

686 also a fine weapon, albeit a little beefier than the K frames. If you want to shoot a LOT of .357, the 686 was designed specifically to handle that. Not that you can’t shoot .357 in the 19 or 66, but there have been rare but documented instances of the forcing cone cracking due to overuse of hot .357s… just something to consider. I wouldn’t let that deter me from a 19 or 66 if they check all the other boxes.

For realistic pricing, it’s helpful to check completed auctions on GB. Gives you a current idea of what people are willing to pay, and just as important, AREN’T willing to pay.

And IF I could only have 1? That depends on the person, but personally I’ll be dead and gone before I sell my blued Model 19 4”. It’s mine forever