You can purchase business for this flight. Some times you get a real business seat and others you just get an economy class seat with a few more inches and nobody in the middle seat. And there is not difference in Price.
Lets forget business and check economy. I am 5'11" (185 cm) tall and my legs were not touching the seat in front of me, they were pushing on the seat in front of me. The distance between seats was not uniform on the flight as rows behind me had more space.
In addition, if you check a bag and are arriving into Madrid, expect to wait about 45 minutes to and hour for the bag to come out. It is incredible. Such a modern airport with such slow service. I guess it isn't all that bad because you probably have to walk for 30 minutes before you get to baggage claim.
I have been flying Iberia for 10 years for business and pleasure and I used to even prefer to fly Iberia but it has got so bad that I do whatever I can to avoid it.