Before a lovely flight on CSA Czech Airlines to Prague from Madrid, my brother and I stopped in the Iberia lounge in Terminal 4 at Madrid-Barajas Airport. The lounge is located just a few steps past security and welcomes OneWorld business class customers, OneWorld Emerald & Sapphire fliers along with CSA business class customers.
The lounge is a large box with a reception desk in the middle, guests are free to enter the lounge to the left or the right. To the left is a computer work area, large open seating area, multiple bar & food areas, a TV lounge and a sleeping lounge. If you go to the right of reception there is another large open seating area and small food & bar area. Food and drink options are almost identical on both sides of the lounge.
Dedicated wine bar, only on the left side of reception. There is a book with a tasting guide and very thorough description of each wine
Alcohol, snacks, and mixtures. Snacks consisted of olives, chips, crackers, olive oil, cheeses, nut mixture and more. Alcohol consisted of a number of spirits from around the world and a number of local brands.
Cold fridge area, it was only 8am, so mainly breakfast items were displayed.
Mini bar/cafe bar along side TV lounge on right side of reception near the back of the lounge. The snack and alcohol options here were smaller than the main food area, but still plentiful and better than what is found in most lounge by US carriers.
TV lounge
Dark Sleeping room for those with long layovers
Large Seating Area, Looks the same on both sides of the lounge & includes a water feature on both sides.
View from the other side of the seeing area
Laptop work station, behind receiption, overlooks runways & ice cream snack station
View from the lounge towards the runways. The lounge is situated above the gate areas, but not immediately next to the edge of the building. 
Business Center. No printer available, but the ladies will print from personal flash disks. Wifi in the lounge is subject to 30 minutes via a scratch card provided to you at check in. I will warn you that these computers are VERY SLOW
Overall the Iberia lounge is a great lounge in a very modern airport. Runway views are not amazing, but still sufficent. Not to mention the food and drink options are great and when I visted around 8am on a Tuesday, the lounge only had about 50 people in it and could easily accommodate over 200!
