Aerolineas Argentinas manage to achieve the considerable distinction of being even worse than Iberia, and that takes some doing.
Their cabin crew are less surly and unhelpful, and their food is better, but their aircraft interiors are in a shocking state, at least they were when I used to fly with them, which was quite frequently, but several years ago. Also their timekeeping was appalling. From what I've heard, nothing has improved.
If I had the choice of IB or AR I'd go IB, but if there was almost any other option (except for Air Comet who are even worse, I'm not sure if they still operate down to BUE anyway) I'd go for that.
If you're travelling on airline industry tickets, you will probably find Iberia treat you better than they treat fare paying passengers.