Cristina's apartment is well located, 3 minutes from the metro and plaza espana, the apartment is extremely clean!! It is a great place if you are planning to be outside all day and just use it for sleep since it is very small, and quiet shady with no view or terrace (ground floor) .
Cristina was very welcoming, she is a great host.
Note that there is no A/C in the apartment, in case your trip is in July and you can get heat wave :)