Welcome to FlyerTalk!

The main problem as I see it is being in Economy transatlantic - and anything that will make it shorter is good; between IB and AA either has little to recommend it over the other and offer a brilliant coach experience.

I will have to say the MAD hub is easy to navigate and between Puente Aéreo and other flights IB has MAD-BCN connected with extensive flight options. With oneworld Sapphire or Emerald status, the IB lounges in MAD are really nice and offer showers.