The subject of porting has come up many times in the years since I began teaching and is still around since I retired. The original was "magna porting" brand. The touted advantage to porting is that it is supposed to help manage recoil on heavy recoiling weapons. I believe the first pistols that Magna Port did were Model 29 S&W .44 mags, way back when. While I have never personally owned or felt the need to port a pistol or use a device on any of my rifles, I have shot a considerable number of weapons that were done by various companies. One rifle smith of my acquaintance, knowing that I hunted a lot with a .375 H&H, asked me to try his latest recoil compensator on a .338 off the bench. It actually unscrewed so that the rifle could be shot with and without same in place. I could detect no difference in either mode. I have found a lot of similar things in shooting pistols that recoil heavily. The negative things that I have noted is that the muzzle blast is increased considerably so that hearing protection is absolutely mandatory or the effect is similar to a flash bang grenade....shocking in big bores. The other thing I noticed on the indoor range where I taught was that the flash that normally would go straight forward is now directed up and out into the view of the shooter. This is highly undesirable because it will totally negate any night vision you may have as your eyes adjust to low light conditions.
When one considers that for all the nice things about small handguns, they are principally made for concealment and self defence, one must then consider under what conditions those may be. Obviously, if we could accurately predict when we were going to need to use a weapon, we would bring more and better weapons than a small handgun and friends also so armed. Since we can't accurately predict it's use we need a weapon that is functional under all conditions and won't hamper our ability to use it while in that act. Porting does hamper your ability. My stock answer in the past has always been that porting can be a detriment in a gunfight. If you feel you need it for recoil control, then get a smaller caliber weapon that you are more comfortable using. If you are thinking about it because you feel there may be an advantage to it on your side....reconsider. The fact is that whether civilian or a LEO, most gunfights occur during low light conditions when perpetrators feel they have more of an advantage. Don't help them out by blinding yourself.