Finally got some muzzle devices and took my VZ2008 and compared six modes: Barrel nut, slant brake, slant brake indexed to 12 o'clock, PKM short FH, Phantom FH, and the Knurled Compensater (Czech/Slovak brake), the last three from CNC Warrior.
The least braking, clearly, was the barrel nut. But not bad.
The slant brake work fine, but with cheek slap, which was reduced, but not eliminated, by twisting it to the reindexed 12 o'clock position.
The point of impact was the same with the Knurled Compensator and the Phantom FH, and about 3" low at 50 yards with the PKM short. The best braking was the Knurled Compensator, then the Phantom FH, and then the PKM short.
The difference between the Knurled Compensator and the Phantom FH was very, very slight. So slight that for my go-to muzzle device I'm choosing the Phantom FH, as at night it will, presumably, minimize shooter blinding and/or reveal of location. I have not yet tested any of the brakes/FH's at night and am going on reputation. I did, however, note the HUGE daytime-fireball that the Knurled Compensater put out, as well as the increased loudness, so I think it's safe to assume that the Phantom FH will perform better in the dark.