First off, good luck getting the 10th round into a G30 mag, so the capacity is really the same - I find it hard to get the ninth one in, but I've got Wolff +10% springs in, too.
In theory, the G27 allows for more CCW methods, but in practice I have found that they are identical, because to effectively conceal either, you must have either a cover, like a jacket/vest, or a CIPS holster (conceal in plain sight), so you may as well go with the G30, IF you like that caliber better. The .45 has more ammo options, and even has unusual ammo options, such as CCI shotshells and Speer plastic bullets for plinkin around the house - the .40 doesn't. The 30 also has less muzzle flip. One other factor on which I will need outside expert advice on, which I've thought more and more about recently, is the noise factor. Is there any credence to the theory that since the .45acp is a much lower pressure round than the .40, it would result in a lower sound compression level, thus damaging your ears less in the unfortunate event of a self-defense shooting?
[This message has been edited by Futo Inu (edited February 22, 2000).]