RE: muzzle break good or bad?
I have seen them affect accuracy on some guns. Especially if the machining is not good. Basically if the brake is machined off, it can cause turbulance on the bullet or can cause inconsistent recoil so when the bullet exits the muzzle it might be closer to one side of the brake than the other, causing pressure differences. I have especially seen this on a traditions inline.
They can be difficult to clean. Added hassle and collect bunch of solvents. I have seen rust from this.
Lastly, makes the gun insanely long for pratical carry. I got friends that swear, they won't take abuse from a rifle and loves them. I figure if I can't shoot it without, I have no business with the gun. There are alot of alternitives. Good recoil pad works wonders. Also you can get a shoulder pad for the range. In the field you won't notice the kick that much or I don't at least.