My wife and I visited Porto for our honeymoon, and stayed at this location. Upon arriving in Porto, we were a bit disoriented and began making our way to find Klaus' home -- we were pleasantly surprised when Anna's mom approached us on the street, and helped us find our way to the apartment!
Upon arriving, we were very happy with the cleanliness and the atmosphere of the apartment -- two large windows that open onto a street where you could simply sit and listen to the light bustle of people and street musicians outside. It was so relaxing, in fact, that we even recorded the noises of the street, to listen to when we arrived back in the states!
One worry that I had was about the noise -- previous reviews had mentioned that it was a fairly quiet location, and I have a hard time falling asleep at night with *any* distractions! However, each night we stayed at Klaus and Anna's apartment, I had no trouble falling asleep, and I slept through the whole night!
Another major perk, besides the ambiance of Porto, was the "Nut Porto" dessert restaurant just across the street from the apartment -- this made for the perfect last stop before turning in for the night.
When we arrived, there was a delicious basket of fruit waiting for us, and Anna's mom helped us get situated with the amenities of the apartment. On our last day, we also requested a slightly later checkout time, based on a walking tour that we wanted to do -- Anna and Klaus were very accommodating for this as well. I would definitely recommend this apartment to others, and will certainly keep this in mind when we visit Porto again in the future!