martin6,
I'm sorry but I don't have or know anyone who has a revolver except for the security guard over at the office.
But a friend of mine had his Glock 26 9mm ported and it seems to have tamed the little glock to a degree.
I have fired it and compared it with my non ported G26 and there is a difference in muzzle climb by about 10-15%.
The drawback is that smoke tends to jet out infront of you. But I think that this is due to the handloaded bullets.
As for decreased velocity I do not think that will be a problem. If this is for self defense then, through statistics, average firefights are well within 15 feet. That's too near to think about decreased velocity, especially with the right type of bullet.
I have never shot the G26 in low light conditions though.
Just a thought, Walther PPK/S or Bersa in .380 for your wife? If you are not yet fully decided on what type of firearm for your wife why don't you check out the other posts.
In a nutshell, IMHO (in my humble opinion), if you think your wife can fire better with a ported barrel then get one (or rent one first). Every little bit counts in helping her shoot well for the time you, your wife, myself, and any responsible person out there, hope will never happen.
------------------
RONIN - samurai with no masters