I have gone through over 250,000 rounds of .22 through various guns in the last couple years. My rating, with 10 being best and 1 being worst:
Taurus 9 shot double action revolver = 2 (Very hard trigger pull, frequent misfires from light trigger strike, spits lead at 90 degrees from front of cylinder more than should be expected.)
Ruger 6 shot single action revolver = 5 (mid-grade gun, certainly not a Freedom Arms or even S&W, but pretty good until thousands of rounds, then starts spitting lead at 90 degrees from front of cylinder more than should be expected.)
Ruger Mark III = 6 (Good target gun for instruction, but as OP mentioned, does not look or feel like a defensive gun… on the other hand, it can help students learn sight pic & alignment, trigger press, grip, stance… well, just about everything another 22 would… . I have three of them, and all took about 10,000 rounds of CCI mini-Mag before they loosened up enough to eat cheap ammo. With hard use, they break frequently and the Prescott Ruger repair shop takes 3+ weeks, which is not appropriate for full-time shooting instructors. Now that they are broken in, I love them! They are a real headache to clean unless you are more mechanically minded than me.)
Sig Sauer Mosquito = 1 (The reason I did not give it a 0 is because it has not blown up and killed anyone. A typical magazine with any kind of ammo, even CCI MiniMag, has approximately 7 failure to feeds. I sent it to the factory; they worked on it and returned it saying it was great. It is NO better. Horrible mistake for a great company to have their name on that hunk of junk.)
CZ-Kadet = 4 (This could be the best .22 of all time, except it has horrible jamming issues. Almost every magazine has at least two jams that are worse than the two basic “fix it” drills will fix. The grip is awesome, just like its momma the CZ-75 (same frame) the trigger is OK, it is made of nice heavy metal and feels like a “real gun” but the jams make it a bad choice. The factory is 3 weeks on a repair, which is not acceptable for a full-time shooting instructor.
I think my next one will be a Buckmark. I have learned the hard way that cheaping-out on gun stuff is a bad idea. On the other hand, the Kadet was over $600 and was worse than the $450 Mark III’s… I would love to find a handgun that I could rate a 10 or even a 9!