This is a great spot for a couple. My wife and I stayed for one week. It's a small studio that's perfect for any couple wanting a stylish place to stay after long days of adventuring in Madrid.
It can take about 25 minutes to walk to Puerta del Sol... which is a nice walk (we averaged 10 miles a day adventuring Madrid). If that's too far, then no worries, you can take the Metro which is only a couple blocks away. The 10 trip pass costs about 12 Euros. I highly recommend getting it... we used it to get around every neighborhood and tourist spot.
You can't beat the price and the value the apartment comes with. Your bed faces a fantastic view with a balcony.
One thing to note is the shower. It is very small but still functional. However, if you are handicapped or very big, it will be a challenge. Also, you will have to bring your suitcases up three flights of stairs (it wasn't a big deal for us, but it may be a challenge for others since there is no elevator). I also do not recommend it for more than two people... it will be hard to get around the room.
Overall, this is a great spot for a couple that enjoys spending most of their time wondering Madrid. It's comfortable and has a nice view. Eduardo and Raul were kind enough to let us check in early after we landed at the airport, and the key is accessible locked away... no need to fetch it somewhere else.
I recommend it!