Brittany used a phrase that I think should be copyrighted - "solid and purposeful." There's not a better description of the 21.
To my eye, the exterior finish reminds me of a blued Ruger Red Label, nice but not special. The working surfaces that I have seen are top notch and we know the materials are good. Like all of the other classic American makers, the gun really starts to shine when it goes upscale.
If you handle enough of the old guns, there's something different about the 21. Try to imagine picking one up when they first hit the market, the new-fangled blued receiver that did not require case hardening, the incredibly tiny bottom rib, and some pretty nice wood. It would have made an impression as "solid and purposeful." People must have thought so back then, because Winchester sold a cart load of them during the Depression when everyone else was sucking air.