Not going to be much different than an A2 for accuracy. In true precision terms (which you may or may not be able to appreciate depending on your skill level) brakes and comps degrade accuracy. Not always, but usually. There is a comp that has actually improved accuracy, but it was set up as the mounting unit for a suppressor, was quite expensive, and I'm not sure that they are even available outside of the .mil.
Not sure what you mean as far as quality.
Any brake that is designed to redirect the blast (and the izzys/AKs do) is sending it somewhere. What would normally go downrange is now being directed to your sides and flanks. Under something as simple as a tin roof on an outdoor firing range it can be painful, and shooters to your sides will not like you much. The y-comp is one of the worst from what I hear, although I haven't been around somebody that uses one.