My unit has a mix of Italian and USA-made M9s. The Italian guns seem a little smoother, but it may be simply that they are older and more "broken in." When I bought a 92FS for personal pre-deployment training, I got an Italian gun, just because it was what the dealer had in his case. It was very well-made.
As a practical matter, I think there is zero difference between the two. Both will be more than accurate enough for the gun's intended purpose (fighting) and utterly reliable. I'd just get the one your dealer has in stock.