The SO where I work issues them to patrol deputies. They're no tack-drivers, but are easy to shoot and are good enough for iron sights and deputies who don't shoot all the time. Our training is at 75 yards, and from a prone position, the deputies put all the rounds where they should be.
It is what it is. An AR generally shoots rings around a Mini, but used to be, the Mini was about half the price of an AR, and perfectly adequate. The Mini (older ones) shoot 55 gr. bullets well, I don't know if Ruger has changed the twist lately for the new heavier ammo.
I have never owned one, and since I have an AR and didn't want one, was never issued one. I've shot most of ours and I helped instruct deputies and get them sighted in, though. Never had any feeding problems except when they failed to seat the magazine (which is pretty easy to do and requires emphasis on training to prevent.) Shot some Wolf steel ammo, and it's nasty and causes rust in the gas system.
Which is another area that needs attention! If you don't put a drop of oil on the piston, it's entirely likely it will rust against the cylinder and lock the rifle up. And you must kick the operating handle repeatedly and finally free the system, not something you want to happen in a defense situation. This happened with several of our rifles using Wolf ammo. I called Ruger and they told me to oil the piston, said they had the same problem with their rifles (not just with Wolf ammo). An unsatisfactory answer, but there it is. A SS gas system would be best.