My favorite has always been the M19, both 4" and 2 1/2", bought this one shiny new in 1986 and carried it ever since, and it shows, but it's honest wear. Always preferred to carry the 2 1/2" for it never hinders me, be it when I'd carry it horseback, sitting in the truck or daily activity, just never know its there.
[Linked Image from i.imgur.com]