Overall I had a couple categories at 3 stars cleanliness/value for some issues explained below, and a few categories at 4-5 stars (location/communication/check-in/accuracy) so this evened out to 4 stars.
location:
The location was very convenient, the street isn't the nicest looking but overall fine.
Value:
The apartment is a nice size but a bit old. The third bedroom is not very nice, it's more like a bed in a closet with no power outlet for charging a phone and unpleasantly bright lights in the ceiling.
The living room was a great space to hang out with our group of 3 and two friends who were staying nearby.
Communication:
Communication with Rui was good, very responsive, helpful, and nice!
Cleanliness/value:
There were annoyances that added up: not enough power outlets, no soap in one bathroom, not enough towels, very little soap left in kitchen, we had to get extra toilet paper.
We had one morning where there was a leak from the apartment above being renovated, which was not Rui's fault at all, but this made the lack of extra towels quite annoying. We found only one.
Don't plan to cook any big meal there unless you want to buy lot of the basics (pepper, oil, etc.), the kitchen is not stocked with sauces and that kind of thing.
Summary:
That's basically it. We had a great time in Porto! but if the place was really well stocked it would have been much better, and the 3rd bedroom really needs improvement :)