I have a Bullberry integral on my 7BR Encore barrel works fine. I shoot smaller rounds, including 6mm TCU, on a Contender with no brake. Most of my Contender and Encore barrels wear rifle scopes and no brake. However, I'm considering a J&P on a .308 SSP-91, got some no name [can't remember] brake and it is still a hand-full. You would probably get the most reduction with a J&P, but Harrell's has a pretty good rep as well.
As others have said, take care of your ears, these things direct concussion back towards the shooter. Also, some ranges are picky about the use of brakes.