craigthemif

Your typical US roll-aboard won't be allowed on Vueling or any other European low cost carrier. Sometimes you get lucky and sometimes you end up paying a fortune to gate-check your roll-aboard. The rules are clear, but nobody can really say whether they will be enforced on your specific flight.

I tend to prefer Ryanair ex-BCN (when there is no major alliance option) because T2 is more convenient for the train from the city and there are far fewer flights (so fewer check-in queues). And with Ryanair once you've paid for priority boarding it is actually enforced and you can rely on overhead bin space for your appropriately-sized bag.

Iberia Express involves a connection in MAD so you'd be better off on the train most likely, unless you have Oneworld status.