I had one made by Gentry called the quiet brake and another that looked very similar and both were ok at reducing muzzle jump and recoil but I purchased a unit from Brownells made by OPS, Inc. that is in a different class. It is used by special forces and has had a lot of research to optimize the design.
I have it on a 300 win mag and I don't think it kicks as much as my 243. The 300 is an 8 pound composite stocked kicking fool and this brake has made it actually fun to shoot. The really cool part is it doesn't seem to increase the sound like the others did. I shot a whitetail this year and didn't have time to put my ear plugs in and it wasn't bad. The brake I had on my 22-250 needed ear plugs and muffs to be able to shoot it. I tried it with ear plugs and my ears rang for two days.