Alvaro's apartment was the perfect base for my trip to Madrid with my Mother. It is in a fantastic location, within walking distance to all major attractions as well as metro lines. Overall, This place totally lives up to all the great reviews, I would go back in a heartbeat!
Because of it's proximity to many restaurants, the front bedroom and living room, which have balconies onto a small street, can be a bit loud at night. But the crowds were not rowdy at all (even on a Friday and Saturday night) and with the air conditioning unit in the bedroom and living room it is easy to shut the doors and reduce the noise. I slept with no problem at all with a little white noise on top of it in the front room and my mother said the back bedroom was dead quiet. It is a small price to pay for being in such a lively neighbourhood with such great food and drink options literally at every door!
One thing to note is that the apartment is up 2.5 flights of stairs, which was totally fine for us, but i someone has accessibility issues it would not be appropriate.
Communication with Alvaro was great and he was very prompt to reply, from checking in to asking where to get more coffee pods. Before arrival he sent out some information about Madrid and recommendations for restaurants and he also offered to call us a cab on our departure. Great host.