We have very much enjoyed our stay at this AirBnB. The location is very nice in terms that it is indeed relatively close to the river and there is a picturesque path along the water that takes about 25 minutes until you get to Ponte Luiz I. The only caveat would be that the airbnb is underneath a train bridge and hence you can hear passing trains every now and then. However, it was bearable and not a big issue for us, but some people might of course feel differently about it.
Other than that, the communication with Oana was impeccable and everything went exactly as foreseen. Hence, I highly recommend to stay at hers while in Porto/Villa Nova de Gaia.