Alejandro is a very kind, helpful and welcoming host.
He gave me some nice tips like what is worth to visit, where to eat good tapas(!), how to move around the city etc.
The apartment is located next to a great avenue with a lot of traffic, however there is no noise in the room because it is overlooking the courtyard of the building making it very quiet.
The whole place is very clean including the room you rent and the shared areas. There is a central air-conditioning in the apartment.
The building is modern and secure. Neighborhood is very quiet and safe.
You can go to the city center by bus, however if you like walking you can get there in around 30 minutes.
There is also a bus that goes to the airport (15-20 minutes ride) and the service is very frequent during the day.
The apartment is also very close to the Santa-Justa train station (<10 minutes).
I definitely recommend the stay at Alejandro's apartment!