I could not agree more with these 2 choices except i would get the mark III that was suppressed...i might get a double action revolver but both of these are excellent choices
I have looked at the 22/45 Ruger with the threaded barrel, have thought a LOT about that. It may be a gun I end up getting as well. But the MK III is for target shooting, my son is interested in getting serious about it. And you can drive thumbtacks with them, they are that good.
The Single 10, well , I guess i didn't play enough cowboys and indians as a kid. I love western looking revolvers....but my eyes love the fiber optic sights much better than the iron ones.