If youre on the fence about the AR pistols (or anything similar), or even if you think they are a waste, Id HIGHLY suggest getting one and spend a little time with it. I put one together a couple of years ago, and now I have 4.
With a brace attached, they are basically a SBR, and now that its legal to shoulder the brace, I dont understand why the stocks arent OK. Still, the brace shoulders and shoots just like the stock, and has the same LOP as my 16" rifles, so everything still "feels" right when you shoulder and shoot them.
All of mine have 10.5" barrels on them, mainly because AAC doesnt, or at least didnt at the time, warrant anything shorter for my suppressor. With the suppressor on, the gun is as long as my 16" guns. Without the suppressor, the blast isnt to bad, and not near as obnoxious as my sons 7.5" gun.
Accuracy is on par with my 16" guns. Offhand headshots on photo silhouettes at 100 yards is not trouble at all, add the suppressor, and even easier with the added weight. 200 yards is probably a realistic expectation of a limit, not that you couldnt hit farther. I look at the 16" guns being a 300 yard gun due to the round losing its ballistic advantage around that point, and Im guessing the 10.5" barrel lost it somewhat sooner. Not that I have any actual eveidence of that.
As a very handy, closer range "rifle", they work very well, and I consider 0-100 as their sweet spot.
Although Ive owned three over the years, Ive never really been a fan of the Minis. If it floats your boat, call Ruger and bitch. Probably wont do you much good, but you never know. A modified factory side folder (or something similar aftermarket) with a brace would give you your "stock".
Theres one other thing with the AR's that you dont have with the Mini's that is actually lacking in their case, and thats the buffer tube. You can easily shoulder gun with just the tube, and use it as a stock. You dont need a brace. Or you can just use it for a cheek weld. Both work OK, but shouldering the tube does work better, especially if you add a rubber table leg cap to it.
Ruger would be smart to go that route, and at least offer it, but knowing how they are, it probably wont happen. Never know though. Mossberg and Remington have seen the light with their 14" shotguns that are hot now, so maybe Ruger will wise up.