We were very happy with our stay here! The apartment is small, clean, and comfy, exactly what you need for a home base while traveling. It is in the heart of Alfama in the historic district, just steps away from gorgeous lookouts like Miradouro de San Luzia and restaurants like Lisboa Tu y Eu. It is a 20 minute or so walk downhill to get to the main downtown area where many tours pick up.
Goncalo and Miku communicated with us quickly when needed. It should be noted that the smell from other reviews was not present during our stay, and should not affect whether you stay here or not.
Overall, 100% would recommend it- we were very happy and loved our time in Lisbon!
Notes: Would not recommend for those with mobility issues, as there are steep steps in the apartment building as well as right around (as is typical in Alfama!).