I think Ryanair have bitten off more than they expected with the 737-800s. They are starting to struggling to make them pay on some routes such as Dublin to Durham Tees Valley. This must be due to the fact that the 738 has 189 seats. When you compare this to other low cost carriers that generally operate 150 seat aircraft you can see the difference and it becomes clear why Ryanair are having to push seats at such low prices. This in turn reduces the yield. The deal they got from Boeing may have been the steal of the century but I think it may start to hurt them. Hopefully they have realised this and change some of the options they have into 737-700s.