" I think the pinnacle of the Ruger line is the Mark III. Just the upgrade from the heel clip magazine release to the magazine release button makes a world of difference."

One worthwhile addition to the earlier Ruger .22s is a replacement magazine release catch on the butt. The standard catch is small and is difficult to manipulate. There is one available which is larger and much more easily released, and it's fairly inexpensive.

Speaking of older Rugers with the butt magazine catch, another recommendation is to file a small bevel on the back surface of the magazine body just above the floorplate. Remove the floorplate and spring first. It makes it far easier to withdraw as the magazine catch will not hang up on it. It takes maybe a minute to do.