From only a pax point of view - and not from the sharp end - being a more than regular user of Iberia - what I have observed from the cabin in terms of safety is a rather preofessional show. Ofcourse you do get the odd one or two crew members who have maybe got out of bed the wrong way - but nevertheless the attention to detail on safety briefings and keeping aisles clear and ensuring baggage well secured in lockers and well tucked under seats in front during take-off and landings is carried out well. When seated in emergency exit locations - crew clearly explain which sometimes bothers me on UK carriers where the occupant maybe has english as not the mother tongue - and often than not the UK cabin crew just go through the drill anyway. Iberia crew - in my experience have a good grasp of various languages - a sad factor differential when flying UK carriers - while acknowledging that English is "the be all".
I have not done long haul with Iberia - but as far as European sectors are concerned - more than happy trusting their ability.
Nivsy