Mediterranean it's a really good hostel. I liked it at all. It's clean, the staff is great - they have a group who serves us paella and teach us how to cook it , and you also can eat it for just 4 euros, and sometimes for free.
Fun sleep is more like a family house, the atmosphere is just awesome because Alex made us fell like home. The room that I slept was very nice, big and very comfortable. I have nothing to complain about this hostel, if I come back to Madrid, I'm sure that I will stay there again!
St. Enoch is a good value place, I got a double room with bathroom ensuite for just 9 pounds per day. The room is very tiny, but have tv, a kettle with tea, coffee and cookies, and they also offer a little breakfast. The problem was the internet , which was not working while I stayed there.
It's a nice place to stay! Very simple but the staff is awesome and the people who stay there too!