As a passenger, I would have to say ineuropa are just as bad as Iberia. For example, earlier this year my return flight FUE-MAN was delayed by 25 minutes, despite the inbound aircraft arriving in FUE on time, all because of incompetent handling - not to mention the fact that they had 180 tired passengers standing in a queue at the gate for 45 minutes (there's very little seating at most of the gates at FUE). They then pulled the same trick when I was returning PMI-NCL in July (granted, there was a power cut in the airport, but the aircraft was sitting there for 90 minutes while other flights were still leaving on time).
The few times I've been through TFS, Iberia handling has been okay, though I've nearly always been delayed it tends to be due to a late inbound aircraft and Iberia tend to be able to turn it around within 45 minutes.
Price is important these days and Iberia comes cheaper than the other competitors, on top of that Iberia can be found at all Spanish airports having only to sign one contract for all Spanish airports
But don't ineuropa and eurohandling handle at airports outside Spain? So can't airlines sign one contract for just as many airports in and outside spain which would bring down costs?