First of all: it was a very, very nice trip and André is the perfect host.
Due to our flight schedule we arrived at the flat around midnight. Nevertheless, André welcomed us in person and took his time to give us a whole bunch of super-tips to explore Porto (museums, restaurants, bars, different city quarters,... - all of them we attended to were great).
He also was available online 24/7. Each of our questions was answered promptly and friendly.
The flat itself is a lovely place to stay in Porto. It's just like on the photos respectively in the description. The main station to go around and explore the Porto area (Trindade) is just a 5 minutes walk away.