Be careful, as the thread has discussed. Just because it screws onto the end of the barrel, similar looking muzzle devices do different things.
A flash hider does that - reduces or eliminates the flash at night. The modified M16 flash hider eliminated the downward slots to reduce kicking up dust. It throws a lot of sound forward.
Brakes are something else. Yes, they very much can push the barrel down enough to be just as bad as no brake. You don't get to use a bipod much in three gun, they aren't issue in the military, and if you are standing squared up with armor plate, your off hand is simply propping up the end of the barrel. Enough force down can and will overcome the pressure up. You'd have to hold it with a firm grip that would quickly fatigue the users.
Some muzzle devices can also redirect the sound to reduce the amount of noise thrown toward the user. I bought a Black River Tactical Covert Comp:
http://www.blackrivertactical.com/product.html
The results of testing posted on the ARP website showed it reduced perceived noise at the shooter's ear a few decibels, less than the standard M16 flash hider. I built the gun for hunting, and I don't wear hearing protection for the one or two shots I might fire in a week long season. Since a suppressor was off the table (tho legal in MO,) I got the next best thing. Recoil reduction was not a priority, even with a 6.8. It works as tested. Under a concrete canopy at a local range, forgeddaboutit. You are toast.
Not all brakes are noisier, not all brakes are even brakes. The real description for the category is "muzzle device," and they do not all work the same. Some are much worse than others for the money, and it seems the more aggressive the looks, the higher the price. I suspect testosterone influences the buying decision more than research and common sense. For the 10X increase in price, it's a serious race gun expense most never see, they don't shoot good enough to notice. It's a Barbie doll accessory.