I don't think porting your carry gun's barrel or buying a gun with factory-ported barrels is such a good idea.
First, there is the muzzle flash. It shows off your location during a gunfight at night. This is disadvantageous to you. While there is still muzzle flash even without the porting (depending on your load), it is much lesser. Also, the direction of the flash in a ported gun is upward which tends to obstruct your view of the sights for the follow-up shot specially under low-light conditions. Finding the sights is already a pain even without being blinded by muzzle flash under low-light.
Second, the loud muzzle blast. If you would ever need to fire your gun inside a car or in an enclosed space like an elevator or in a parking lot (it echoes), you'd better have your earmuffs on because the sound would be intolerable. It might stun you enough to delay your reaction time for your next shot. The loud sound is not only comes from the escaping gas but from the combustion going on in the ports specially when using slow burning gun powders. A short barrel aggravates the situation.
Third, every hole slows down your bullet's velocity by 5 to 10 ft/sec (forgot the exact value) depending on the size of the hole. This is important in self-defense since most expanding bullets depend on velocity for proper expansion and penetration. There is also a school of thought in the knocking power subject which says that the best man stoppers are light rounds traveling at a high velocity (think .357 magnum or the 5.56mm) - JHP or FMJ. Therefore, slowing the bullet down is not a good idea.
Fourth, the mass of the gas escaping the ports would be lost mass for pushing the action back - this affects those designed with a direct blow-back operation more than those designed with browning's breech locking mechanism. The result would be a jam action like a failure to extract, failure to eject, and a stovepipe (a special kind of failure to eject).
Fifth, they introduce gaps where mud and dirt may enter when the gun falls down or when shooting prone and rolling or crawling on the ground. The dirt would get stuck between the slide and the barrel hindering proper operation.
If you want to have better control of your weapon, do the following in the order given:
1. bring your gun to the range and burn some lead;
2. use a heavier gun or one with a low bore line (axis) like the Glock, SW Sigma, etc.;
3. use a lower caliber handgun; and,
4. use a properly designed integrated compensator (different from a port!) like the one found on STI's Trubor.