I stayed in Mario's apartment for one week working remotely while in Porto. Overall, I had a good stay. Let me just summarise some pros and cons:
Pros:
- Great location. Super easy to walk to everywhere, and nice bakeries and restaurants very close. Also easy to get to the airport by metro (station 15 min walk away)
- Flat is very bright and nice during the day
- Convenient check-in with lock box just across the street
Cons:
- Traffic from the street is very loud, even through the night, and with the windows shut. Not that great for working, but if you're coming as a tourist and will mainly be out all day then it's not a big issue.
- No air con, just a fan (although I think this is standard in Portugal) so just expect to be quite hot in the summer! Not really possible to sleep with the windows open because of the traffic noise.
- Shower is a bit of a nightmare but I've already suggested an easy way for them to improve that
Overall, I enjoyed my stay, and would recommend this flat to tourists who are not light sleepers!