I stayed for a week at Paulo & Caroline's place. It couldn't have been better. Perfect location (not ultra central, but instead very calm and quiet neighborhood at night just a short walk from everything), beautiful old house and maybe the most lovely hosts so far in my experience on Airbnb. Paulo and Caroline will make sure you'll have a great stay and they are very easy to communicate with. I will look no further for my next visit in Porto. Highly recommended.