We wouldn't recommend this apartment. I messaged the host regarding check in twice in the days before arriving with no response; when I tried Whats App one number was for someone who no longer works for the apartment and the other was for a check in service that failed to respond. We finally got a response about a half hour before arriving in Porto with the lockbox instructions - and when we located the lockbox it was unlocked; anyone could have accessed the keys.
The apartment itself looks great in the pictures but is more dated and has more wear and tear in reality. It had been 'cleaned' in the sense it had been wiped down and beds made, but not mopped - there was sand on the floor. One set of sheets had stains and tears on them.
The location is easy enough for exploring Porto but the street is dark. We were three young women who had safety in numbers but I wouldn't recommend to a solo traveller.
Finally, there is only one set of keys - a logistical nightmare when you all split off and explore the city separately. We had to constantly co-ordinate to exchange the key if someone needed to go back to the apartment and others didn't.
In general, it was just not up to the standard you expect from Airbnb.