Hi, I have flown to Europe a number of times but only on AA or NWA. DH and I are taking a cruise out of Barcelona and plan to also visit Madrid, so will do an open jaw. We are flying out of Chicago and will have to change once for Barcelona. A lot of airlines to choose from. Any better or worse? How about Iberia (we can transfer in Madrid).
Oh, we fly coach class.
Most of our miles are on AA and NW (now Delta).

If flying economy then pick the airline that either has a non-stop or 1 connection with the shortest route. Some here will probably suggest connecting through London but at the end of the day you have to ask yourself a question if a free drink is worth extra few hours of flying or connecting?

AA or Iberia should be fine for your needs. Iberia will have free drinks. Both are about the same in the economy food department. AA will be much better in the customer service department if for some reason you need some help.

I would recommend flying over on Iberia and back on American. I've seen tickets available like this.
Why? Iberia offers free drinks in economy and there will be a duty free store in Spain where you can purchase something to drink before you get on the plane.

If American is using a Boeing 777, that is a plus. The entertainment system might be a bit better on American, but if you are planning to sleep then it won't matter.

If you book from JFK to Madrid on American, you will be flying on a code share on an Iberia Jet. I've found their economy service the same as other airlines and you get a bottle of wine. They usually use Airbus 340s.

have flown Iberian Madrid to Chicago and the aircraft was very dirty around our seats, partner's seat broken-not impressed.

I flew Delta to Madrid from JFK last month ... coach. It was fine - seemed to have quite a bit more leg room than when I flew to Madrid a year earlier on NWA, although I realize they are now the same. It was a Boeing 777-200/300, according to my itinerary. Must be a different aircraft than NWA was using.

Food was typical crummy airline fare, but there was free wine and beer.

One note ... the headsets for the back-of-the-seat video screens are terrible. Not sure if bringing your own would help at all, but don't count on enjoying any of the movies unless you're really into static.

I was bumped from an Iberia flight from Madrid to Chicago several years ago and it took me one year of phone calls and faxes to get the refund that was due me. I would never fly them again.