We enjoyed staying at the Tiles House. I'll divide my review into people, apartment and location.
People: Right from the beginning Diogo was quick to respond to mails and questions. We were genuinely surprised and made feel welcome by Diogo and Cousins picking us from the airport. We were met be Diogo's cousin Cesar, who told us that airport pickups are routine. Cesar gave us a ver nice and detailed introduction to the apartment and surroundings which were of great help.
Apartment: The house itself is comfortable for 4 people (we were 2 adults 2 kids), and most importantly for summer has air-conditioning! There is a convenient kitchen and a single bathroom. Please note that there are 48 steps to the apartment and the first section is a bit steep, and may not be appropriate to those with difficulty in climbing. That being said, for us climbing daily was no problem.
Location: Fabulous. Located on a flat street minutes from Baixa and the cathedral can be seen right next to the apartment. There is a tiny grocers 2 steps away, a minimarket in the next street, and a supermarket (Pingo) just 10 mins away (for going to Pingo be aware that there is a very convenient and free elevator from Baixa to the street where Pingo is located). We walked everywhere and without issues.
Final Word: fantastic people, apartment and location. Will not hesitate to stay here again if back in Lisboa. Highly recommend.