The only negative aspect of staying at Diogo's place is that you don't want to leave the apartment! Alas, we had to get out at some point, and go about Porto.
If I had to describe the place with one word, it would be - suave. I strongly recommend to everyone visiting Porto to stay at this apartment. Just play some jazz on a large bluetooth speaker provided at the flat, and enjoy the sparkling clean, well arranged and tastefully decorated ambience of Diogo's place.
I give it 5 star rating, without a shred of doubt.