We were extremely pleased with our stay at Andreia and Rui's place in Porto. They met us at the apartment and gave us a map and tips on what was close. They also clearly explained how everything in the apartment worked. One thing I always wonder about AirB&B's is the smell, especially in old buildings. Rest assured, it is a modern remodel with new beams and everything and it smells fresh! One downside is that though the outdoor space is really nicely appointed, it sits above a very busy street, so it's a bit too loud to be pleasant. However, there's a shared outdoor space on the other side of the building, and while it doesn't have the great seating and décor like the private one, it is quieter - or at least the sounds are more interesting - it faces the back living area for lots of people so you can take in some of the sights and sounds of the city.
We were there in the summer, and the AC works great. The hosts had lots of nice touches, like pastries for us on arrival, and cute décor. Would totally stay there again.