First, let's talk about location, you can't beat it. It's within walking distance to the Palace, Plaza Mayor, Mercado de San Miguel...you name it! It gave us that "living like local" kinda feeling, which we always love.
Plenty of space for 4, two large bathrooms, air-conditioned, the smallest elevator we've ever seen (I say this as a complement, because that's why we love Europe).
We loved our stay for 5 days and highly recommend it to everyone who travels to Madrid.