Hi Keith,
Is one better than the other? Well, I'll set some of the pro's and con's here in this post and you can decide for yourself.
Both muzzle brakes and Mag-Na-Porting use the expanding gasses of the cartridge to counteract muzzle flip and, in some cases, mitigate recoil somewhat by directing them backwards slightly, towards the shooter.
With a muzzle brake, the end of the barrel needs to be threaded and the brake installed square and true to the line of bore, otherwise the projectile itself will contact the brake and bad things will happen. There is no loss of velocity with a muzzle brake, since the overall length of the barrel remains unchanged. Brakes tend to be better engineered and mitigate recoil and muzzle flip better because they're self-contained units. Designers are free to do what they want with regards to fluid dynamics (air is considered a fluid when it comes to engineering, I won't go into it any farther than that) in that respect. There may be a slight loss of accuracy with your preferred load, since having a brake on the end of the barrel will likely change the whole dynamic of the barrel's "whip", which is the way it vibrates after the shot is fired, but before the projectile has exited the barrel. It may act as a dampener, and somewhat limit the vibrations, or it may make them worse. There's no sure way of knowing what it will do to accuracy until after it is installed. It may even enhance accuracy, so installing one may be beneficial to accuracy.
Mag-Na-Porting is efficient, and the big benefit of having it done is that there is nothing hanging off the end of your barrel, so there is usually no degradation of accuracy. 6 ports are more effective than 4 when it comes to mitigating recoil simply because more gasses are being deflected, meaning there is more force counteracting the forces of recoil. Velocity does suffer, however, since the force of the gasses are being used for something else other than propelling the projectile before it has a chance to exit the barrel. It is most pronounced in "magnum" class calibers, since they make their reputation on velocity. Bleed off enough gasses, and the projectile isn't moving as fast as it could, which affects downrange performance, though if most of your shots are inside 200 yards I doubt it would make much of a difference as far as the game animal is concerned (unless it were something large and angry, like a Cape Buffalo).
That's about it. Trade velocity for recoil with the Mag-Na-Porting or perhaps affect accuracy for recoil. Of the two, I would go with the -Porting, just because I know that where you place the bullet is more important than how fast it's going when it gets there.
Pz