The OPS Inc. brake isn't as loud as brakes with more ports, those also seem to work better at reducing the muzzle flip. When I got the MSTN QC brake from Wes of MSTN, his repeated forewarning was that the .223 version works better than the .308 brake. This isn't to say the .308 is a lessor brake, only the .308 round generates so much energy, it mitigates some of the effects of the brake.
The OPS Inc. brake's front end is hollow like an expansion chamber. As stated, to my dismay, the flash suppression was better than a naked muzzle but the JetSuppressor's 4 port brake was better, at least with the ammo I used. In full auto, with the OPS Inc brake and 9mm buffer (on an MRP with a PEQ2A and Surefire M900 on it...heavy!), I feel a gentle push. Same lower, 11.5" heavy barrel and RAS and JetSupressor's 4 port brake, I don't remember, probably because I felt too little to notice
Even an A2 compensator/flash suppressor helps to reduce it, it just doesn't work as well. Last week at the AZ MG shoot, the blast enhancer/4port brake on my HK51 was loose and would spin when a long burst was fired, it was hilarious to watch the muzzle make a circle in long bursts as the brake directed gas in all different directions, as if the shooter was making an O with the weapon
This video illustrates the effect of a brake spinning on a short barreled .308 in full auto
here