Out of my own experience, I would never ever take Iberia again. Had many many flights with Alitalia and was mostly ok. Iberia had also many flights but almost every time with problems involved. Once, had incoming flight late and next flight did not wait for us. Iberia refused to book us on a later flight. Argued our tickets were for that specific flight only and that's it. Had to buy new tickets and go through the whole hassle with complaining to Iberia and to deny payment with credit card etc etc. Was very time-consuming and frustrating. Had never such problems with Alitalia. Hence, would take AZ if I were you.