The stay at Mario’s apartment was okay. The arrival and check in worked without any problems and everything was fine. The room does exactly look like on the photos and is nicely furnished.
The neighborhood is great. You just need to walk a few steps to be at some important spots in Porto. If you have a light sleep it may be a bit noisy for you because the apartment is located in a street with some bars and restaurants. For me this was no problem. :)
Sadly there was a problem with the cleanness. At first glance everything looked fine, but I am sad to say there were a lot of ants everywhere. When I told Mario he answered directly and tried to help me with this problem though he was on vacation himself. He offered me to leave earlier or to clean everything myself.. I decided to leave and look for another accommodation, because I did not feel comfortable there.
But if he solved the problem with the cleanness I would recommend the apartment.