The appartment is very nice and cozy. There's lots of light, and we slept wonderfully (total silence!).
It's a bit far from the touristic area and the metro station, but there's a bus stop less than a block away and taxis are cheap in Porto (5-7 euros at night from downtown to the ap)...
There's a cafe just beside it, great for having a real portuguese breakfast!
The hosts are very helpful.
Everything was fine. I definetely recommend it!