I stayed in the Hostal for one night in January 2012 and it was overall a positive experience. The location is perfect; within easy walking distance of the city centre and extremely close to Opera metro stop (2 doors left of McDonalds). There is a lift up to the Hostal reception which was a huge bonus and the man on reception was lovely (although I'm not sure how good his English was).
I stayed in a single room facing away from the street so it was very quiet although the view was incredibly uninspiring, consisting of a wall and a few a/c units. The room and bathroom were small but clean and the shower had plenty of hot water and was very powerful.
I couldn't find any sockets to plug my laptop charger into, although that could just have been me not looking hard enough.
There is a computer on the 2nd floor where you can access the internet although it wasn't working on the morning I was there.
The 24hour reception is good and I felt very safe leaving my suitcase in a little side room while I explored Madrid after checking out.
Overall a great bargain in a perfect location, possibly better if you speak some Spanish although the cleaning staff seemed to speak pretty good English.

I visit Madrid often to viit family and this is always my first choice of where to stay ...

It is right in the centre of Madrid, excellent value, clean and secure. I have stayed at least 6 times in the past 2 years and never had one problem. The staff are friendly and the rooms are cleaned to an excellent standard every day. Rooms are air conditioned aswell so when staying in the summer months it is very comfortable.

I always email and ask for a quiter room away from the main road however on the one occasion I forgot I did not find the noise from the main street ... a lighter sleeper may do though so just ask them if you would prefer a quiter room.

The hotel has free wifi aswell which is great for keeping intouch when staying away from home :)

Would recommend staying here to anyone.

Just repeating what all the other positive reviews have said - a great location (next to the metro, in the middle of the shopping and restaurant area) and safe, clean, comfortable rooms. For the price, it is hard to beat. Staff are friendly and accomodating. Yes, if you have a room that opens onto the street (as we did, on the 2nd floor) you will hear noise coming up but only take that as a negative if this sort of thing bothers you (it doesn't bother us). Madrid is a city that barely sleeps, so the noise is there all night as well.

Pros:

Room very clean

Excellent Location - right by Opera. To get to the main shopping are turn right and you're pretty much there. Turn left out the hotel to the Opera and Palicio real.

Very reasonably priced

Check in and out quick and efficient

There is no breakfast, this is not a problem as there are plenty of places to eat nearby e.g. Cafe et te which serve food. There is also a McDonald's practically next door to the hotel.

Cons:
You will need to have some knowledge of Spanish, when I was there 2 members of staff on duty spoke no English. Thankfully this wasn't a problem for me however it was for some other guests. If you don't have a basic grasp of Spanish you may wish to consider somewhere else.

I had a single room on the back which was fairly quite in terms of noise from outside the building. However one could clearly hear activity in the corridor.

Not much space in the toilet cubicle, not a problem for me but possibly it would be if you were generously proportioned.