I started using a lot of 'em, after Remington discontinued the CBee Shorts. They're nice and quiet, plenty of accuracy at short back-yard range for starlings and grackles, and plenty of power for quick kills on raccoons, cats, etc. with HEAD SHOTS ONLY!
Plus, they have a huge advantage over any 22short cartridge in that they have a case the same length as a 22lr and therefore don't mess up the chamber of any gun that you use to shoot them in large numbers. I've put about 500 through one gun in particular (Ithaca 72 lever action) and can still chamber a 22lr with no problems.