I absolutely recommend this place to anyone planning a trip to Porto.
Graça was a superb host, very responsive and helpful both before my trip and throughout my stay.
The flat is centrally located, supermarkets as well as public transport links are within walking distance and it is a great base from which to explore everything the city has to offer. The flat is located on a busy road and the traffic sound can definitely be heard in the bedroom, however, it was not such that it stopped me from sleeping.
I visited on a working holiday and found the internet connection to be fast and stable.
Overall I had a thoroughly enjoyable stay at Gracas apartment - highly recommended!