Antonio's place is a little hotel in the middle of Porto. You get a room with a comfortable bed and a balcony. There is no shared or common area to hang out, but that is not really needed when you are in a city as beautiful as this one.
The whole place was very clean all the time, including the toilet and showers. Everything else is exactly as described in the listing. I have nothing but good things to say about this place.
The only negative thing is not really Antonio's place fault, and it's about the noise on the street. We stayed for 5 days and this only happened on Friday and Saturday night. I didn't have much problems with it. Only woke up a few times during the night and fell back asleep immediately. But if you are a very light sleeper, this can be an issue. From midnight until 4 AM or so, the people coming out of the nightclubs located on that street will make all kinds of noises.