I just got my Irish passport today (I have my U.S. passport too). When I have gone through airports in Europe (just recently to Italy) I had gotten a connecting flight in Paris.
By the time I had gotten through the 200+ people line waiting for passport control, I missed my next flight. The EU line had no people and the few went right through.
So I would like to know for instance when I do a trip like that again, once I get to a European airport can I just go through the Schengen country line instead of standing in the non-EU line passport control?