Christina and Elizabeth (the lady welcoming us) are fabulous. Elizabeth greated us ready with hot tea, pastries and fruits upon on our arrival, which is greatly appreciated after a long travel. She gave us a map, told us the must see, and gave us fabulous restaurant recommendations.
The appartment is very well equiped and is super clean: bed and sofa bed are very comfortable, great shower, kitchen is well equiped (good coffee!) and the little terasse is enjoyeable. It is obviously a high standard appartment that can easily suit 2 couples. Wifi works perfectly. 2 little downsides: not as close as it could be from the action (but we prefer that as it is calmer!), and the appartment door is not well isolated so people speaking/walking/slaming doors in the corridor could bother you. As a previous guest said, everyone should be concious of others and be calm in the hall...
All and all, I would definitely recommend, and also will go back for sure if I am in Porto again.