Rui en Sergey were really friendly hosts. It started we we arrived in Porto. Our flight arrived very early and he had no problem with us dropping of our luggage this early, even if the normal check-in was at 15h.
The apartment is really nice. It's not very big but it has got everything you need. The room also is't very big but you've got enough space to put your stuff. Everything in the apartment was very clean.
We asked to use the kitchen and he gave us our own space in the fridge and in a cupboard.
The apartment is not very close to the historical center, but the metro is only a 5-10 minute walk.
We had a really nice stay with them in Porto!