This Madrid hostal ( Hostal Bianco II ) is listed on this website along with other Madrid Hostels, but I would avoid it as I had a very bad experience there just a few days ago. The hostal is centrally located just off Sol, clean and nice, but all my problems arose from billing. I was overchaged 90 Euros on my credit card when checking in, and the manager wanted to give it back to me in cash, only after charging me a 12% commission that she said her bank charged her. Not until I theatened to call her bank (BBVA) on the spot and report her did I manage to get my entire overcharged amount back. Upon returning from dinner that night I was stopped when I entered and told I had requested 3 nights, not the two which I had already paid for. So, the next day I had to find a printer to print the actual email I had sent to them with my request, so they would not charge me for the 3rd night, which I never requested in the first place. I had my confirmation email, but the confirmation they send you conveniently does not have any dates printed on it anywhere.
Again, it's a clean place in a good location, but they seem to want to make a buck at any expense. I have stayed in many hostels in Madrid (two from this site- Hostal Alistana and Hostal Hispano , both excellent) and never had a problem like this one. This place certainly seems to be the exception to the usually friendly and accommodating service you find in Madrid.