I've handled both and the Italian ones sometimes have a little smoother finish. But I've read that the US ones may have more consistent workmanship.

Mine is US-made and I like it very much.

On the Beretta board, this gets asked quite a bit, and the consensus seems to be that there isn't much difference.

Keep in mind that the older German SIG's had slide rails that cracked until they were made thicker and the slides often rusted.