My experience is that the AR-15 platform does not work well as a handgun. That straight-line setup that works so well as a shoulder fired weapon makes it extremely "flippy" as a pistol, only being semi-practical when held with a firm grip on the front.
It was never designed to be shot with one hand, and I wouldn't really catagorize it as a handgun (regardless of what your brilliant legislators try to classify it as). It was specifically designed to be used with two hands, just like an SBR, but without the stock. And, because it's only a semi-auto there really is no need for the stock. You can learn to shoot it and be quite accurate with it - it's just a little different, that's all. In fact, it's one of the few guns where I find that a laser truly enhances its usefulness.
The noise is also nearly unbearable unless you wear double ear protection in the form of both ear plugs and ear muffs.
The preceived noise is only slightly more than the same gun in a rifle version. Sounds about like a .44 magnum (I tend to shoot it when I get my Desert Eagle .44 out to shoot) and I shoot mine all the time with just ear muffs without any problem. But, if the muzzle blast is a problem, then just swap out the muzzle brake for something that doesn't direct the sound energy back toward the shooter.
The muzzle flash is pretty darn impressive, especially this time of year when it's so dark anyways. That's a good thing for impressing your friends but a bad thing when you think of any real-world uses.
I'll give you that - muzzle flash is quite bright without a much larger flash hider.