OP, what rifle are you putting this on and what is the diameter of the barrel at the muzzle?
Lots of good recommendations in this thread. Seems the primary two items that will impact this is the angle and size of ports-brakes that direct gases rearward with at an angle up perform best. Take a look at the features of the brakes that performed well in this test:
Muzzle Brakes: Ability To Stay On Target - PrecisionRifleBlog.com
The ports on top make sense for reducing muzzle rise but ive seen slow mo videos of sporter contour barrels in magnum calibers with top ports bending the barrel significantly at the shot from all the downward force.