You know, my personal problem with .380 isn't so much the round itself, as I think modern jhp designs overcome a lot of the past inadequacies of .380. It's that .380 is typically carried in pocket pistols, like my LCP, that I can't shoot worth a damn with. I'd feel 10x more comfortable carrying a .380 that I can actually shoot with, such as my Bersa Thunder. Of course, I wouldn't bother carrying the BT, when I have a PT-709 and a PF-9, which are 9mm's and smaller.
So, yes, I'd carry a 9x18 if it's in a pistol I can shoot with. I have carried my cz-82 in the past and did not feel underarmed at all. 13 rounds in a reliable gun with a great trigger that I can shoot well with ain't bad for carry.
Of course, for the weight of my cz-82, I can carry my G27, and move several notches up the ladder in terms of ballistics.