I don't care for brakes, i have them on a few and some i have taken off. I personally don't see the need for one on a small caliber weapon. but that's just me. Plenty of people swear by them. but i hunt with most of my newer AR's and having to wear ear protection while hunting is a pain. brakes are fine on range toys where hearing protection is required and needed.
I am not a sniper or sharpshooter and don't need to hit a dime at a 100 yards every time, just need to put the animal down quickly without it running for a mile. now for me i didn't see any better groups with or without the brakes. but i also don't reload and all my rifles are factory built.