The location is great. Close to Thyssen and Prado museums. Also close to shopping (Gran Via) and theatres. Check in process was great. Helena shared details prior with us and that worked out well.
The terrace is great if you want to sit out or sunbathe. The bed was not long enough (if you are a tall person [> 6 ft], please take note). Air Con was great on a warm day. There is no kitchen (if that is important for you). Super in great! He greets you warmly. There is coffee shop (friendly lady) and places to eat close by. The convenience/alimentation store owner wasn't friendly (no leche!, no black tea! :(
Price wise, I found NH Hotel a block away for 10% cheaper; for an extra day.
Had a great time in Madrid. Thank you Helena for hosting us.