I think that Armalite makes the best brake out their for the 50's but its huge and ugly. Basicaly all of the better brakes for the 50BMG are just baffel brakes , the bigger the ports and baffels the better the recoil reduction , but alot of the big 50 brake angle the ports back toward the shooter so that the gas doesn't go out to the side but actluay backwards causeing the gun to actualy be dragged back forward , this is the reason for needing a realy tough scope on them , ironicaly spring piston air rifles need the same scopes quality.
I have shot the AR-50 from Armalite and the recoil is not bad at all maybe like a 270 or 30-06 , I've also shot a Barret , Cobb , Robar and some cheap piece of crap. The cobb kicked like the Armalite , the Robar RC-50 kicked about like a mild 12 load , the barret kicked like a 3" mag 12ga and the cheap rifle kicked like a mules !!
The brake on the Robar RC-50 doesn't look to impressive its not much bigger than the barrel and is just a "gill" style brake , I was prepairing for a nasty kick but it works very well.
Nathan Dagley makes some great brakes as does Shawn Carlock and Kirby Allen , thesize of the brake is kinda relitive to the round and the rifle , a realy light weight 338 Snipe-Tac is gonna need a bigger brake with more baffels but a 243 doesn't need much at all.