Your picture shows an AK74-type muzzle brake.Why the preference for the Vortex over the AK74 type pictured here
A flash suppressor is intended to reduce the visibility of muzzle flash (from the perspective of the shooter) to preserve night vision. The flash is still quite visible from the perspective of the target. Flash suppressors work by rapidly expanding and cooling propellant gases as they leave the end of the barrel. The density and temperature of any remaining burning powder are greatly reduced along with the brightness of the flash. Flash suppressors may have some positive effect on muzzle climb, but that is not their primary purpose.
Muzzle brakes or compensators, on the other hand, are intended to reduce recoil and muzzle rise during rapid fire by redirecting propellant gases. Escaping gas creates four effects: noise, pressure, blast, and flash. Noise increase is necessary to most designs because higher velocity gases impart more energy to counteract recoil. Higher velocity produces greater noise. Pressure is felt as a shock wave similar to that made by an explosion. The blast is the physical movement of air. This has the effect of blowing up dust and debris from below and to the sides of the brake. Finally, flash is generally increased as the high pressure gasses mix slowly with surrounding air, staying hot enough to glow for a longer period of time.
Two different tools for two different purposes.
Here's a nice video of a flash suppressor in action: