I prefer the fish gill type brake (typified by Holland and Micaluk). These tend to reduce recoil the most. The wider the brake and the more baffles per given length, the higher the recoil reduction potential. The Micaluk brake is the best deal in brakes today if using a barrel with a muzzle under 0.800 to 825". The JP brake is one of the most effective if you don't mind having a rifle that looks like it belongs on a Sherman tank.
Any brake that vents forward (ie VAIS, angled ports) reduces the effectiveness of the brake but can also reduce the noise signature to the shooter.
Any brake that vents backwards (ie Armalite) increases the effectiveness of the brake but will also increase the noise signature to the shooter.
A single chamber brake with lots of perimeter holes like a KDF is only as effective as the total surface area of those holes. Size, location and pattern serve little purpose. The brake that vents the most amount of gas sideways (biggest surface area of holes per given length) wins.
Baffled brakes are usually more effective then single chamber brakes of equal length and diameter.
Keep the exit hole within 20thou of bullet diameter (not under). The bigger the hole, the less effective the brake and it doesn't take a huge increase to really make a brake ineffective.
Jerry