Does it being ported affect the velocity or power of the bullet /gun? I would think that with the gasses escaping it would have a neg affect to the power and speed.. I mean I'm no expert but that's what I think..I personally don't like ported barrels. They are louder, and if one is not carful, they may be sprayed with hot gasses escaping from the ports.
How's the hot gas situation when firing from retention?I have one, probably my favorite gun to carry. The recoil is less than the non ported version, the sights are awesome. I have not been sprayed with gunpowder or anything like that. Some people worry about night vision being ruined by ported guns, I don't have that problem myself. Maybe rent one at a range or find somebody that will let you shoot their's then you can decide.
While I agree the flash isn't any brighter, it does pop up right in front of you. This can be and is a problem with me personally. It causes a pretty big burn in, in my vision while shooting in the dark. As always, YMMVThe porting on the pc Shield isn't really decisively a pro or a con in my opinion. The porting does work to a degree but I never found the Shield to be too muzzle flippy. The porting does not cause any flash brighter than the non ported flash - it does cause a predictable v formation flash but it is not bright or blinding by any means. Let's also remember non-ported barrels cause flash albeit more irregularly occuring and just different looking than the ported.
Anyway, I wouldn't buy the PC Shield for the ports, I'd buy it for the trigger and only if I liked fiber optic sights. I would really ignore the ports for most intents and purposes. If I was going into a Shield now I would get the night sighted non-safety model and add an Apex trigger/action enhancement kit. Remember, the PC Shield mandates an external safety. Also, don't forget to augment the grip somehow - it helps on this gun more than you probably realize. (e.g. Talons - Hogue grip cover)