Very clean, perfect location right in the city centre of Porto. Plenty of Restaurants, Bars, Cafés nearby. All spots you have to visit in the city are in walking distance as Porto is not that big. There's a good restaurant just downstairs.
No problems with the check-in. They offer a pick up service from the airport which was perfect for us. We were awaited at the appartement.
The appartement ist modern and very clean but a little dark and soulless. A typical Airbnb-only appartement. It's good for a two day-stay in the city.