The hotel is in a great location on the Gran Via. Get the Airport Express Bus (currently 5 Euros), get off at Ciables and the take Line 2 on the Metro from Banco de Espana to Santo Domingo and you're there.
I booked this for the use of the pool after the Madrid Marathon. Very dissapointingly it was kept closed with no explanation.
The rooms are nice, but the walls are thin - expect to hear everything from the rooms around you.
Breakfast buffet is fine, your place is instantly cleared the moment you get up.
The location is great, use it as a convenient base.