We enjoyed Vitor & Anna's place a lot. It is brand new and in a safe and quiet neighborhood. The studio is small, but the space is used well. We found everything we needed. Vitor is a great host and greeted us with a watermelon and some water - even though we were two hours early! The next metro station that brings you almost anywhere is just a few minutes away and there is also a small mini-market around the corner.
If you arrive by car you might not be able to park it in the same street as it gets quite crowded at times. But we had no trouble parking in the parallel street just a minute by foot away.
We highly recommend this place if you visit Porto!