Don't get me wrong...I'm not maligning the 9mm, or any other cartridge. I'm not enough of an expert (to say the least) to make statements. I was just reinforcing the sentiment of another poster who astutely pointed out that the 9mm has a gotten a lot of press for being insufficient at stopping a Bad Guy [tm]. There's far less apocrypha about the .4* ammo.
That said, I'm curious as to why you say the comparison is "not practical."