Other reviews have it right. The main point here is the location.
You are in the heart of the action in Madrid! The street the hotel is located, is one of the main places to find good places to eat, drink, and party, if that's what you want.
But be aware, that the hotel conditions are OK at best.
The hotel is on a old building (as are all in that neighborhood, to be fair) and things don't have none of the modern amenities that you would expect at this time.
I can only speak from the single room I stayed in, and it is a very budgety place.
Tight space, with a very old personal bathroom. The shower head is detachable, and you have to very carefully get into a small bathtub to take your bath.
The bathtub is not big enough for any adult human being be able to use it as a bathtub, so why have it? It's a liability since you can easily fall trying to get down from it after shower.
The doorframe of the bathroom also is in a really bad shape, and don't close properly, as the wood is stuffed. Meaning that the smell of the bathroom goes all the way to the bed, and it can get nasty.
The bed is very good, very comfortable, and is a twin bed, a big person can sleep alone there comfortably.
Summary: location is awesome, but be prepared to not have any comfort. And don't kid yourself that you will go out in the morning and just come back to sleep at night.
Nobody actually does that every day during a trip. Sometimes you need a place to just sit and rest.