I'm rating this with 3 stars after I had to deal with a blackout of several hours (only the unit was involved, meaning it was not a general blackout), during our first 2 days.
The stay was comfortable and very well located. The entire apartment was very clean and kitchen was well set with everything.
What it could be improved? some furniture is not in very good shape, and it would be good idea to change them (not big investment at all)
Other than that i would recommend them for staying at PORTO.