I have one of the Sub-2000's, and I like it for what it is. It is my packing/truck gun. I consider it to be a gun to be carried alot and shot a little. I do shoot it quite a bit for fun, and such, and have had good luck, but as far as a working rifle, I think you are definitely correct. Too many good AR's out there for day-to-day work guns.
A couple of things I notice on my gun, the front sight seems to flex where it connects to the butstock when folded. I am sure this will affect POI. Also, when inserting the mags into the pistol grip, many times the 2 halves of the grip seperate slightly, and the mags seem to bind a bit. They still go in, but again, polymer does give some.
I am pleased with the little rifle. Light, handy, very compact storage. I wouldn't hesitate to get one of the .223's either. I just wouldn't use if for my working rifle. Really neat idea. And, it does make me feel better knowing it is there, just in case.
Again, mine is .40cal Sub 2000, not the .223.
Maybe this helps, maybe not
Good luck
Doc