We stayed at Marco's place in Porto for two nights in late July. Marco was flexible with our check-in time as we were driving from Lisbon to Porto on the day of check-in. Marco also gave us some local tips, e.g., where to find restaurants and places serving port wine :)
The place itself was awesome. The house is sitting on a hill and provides unobstructed views of the old city and the river. I would definitely stay here again if I were to visit Porto again.