I would definately recommend this nice place! Quick response, clean apartment, good spot, warm welcome, everything to make my stay in Porto wonderful. Eugenia gave me such a nice welcome when I arrived at the appartment.
Just around the corner in rua sao joao there's a great restaurant to have breakfast or dinner. Restaurant D. Tohno at the water near the Dom Luis bridge is also very nice.
I was by myself, but the place is also great for a couple or two friends.