Great value for the Price.
Plus:
+The appartement was spacy, with a big and comfy bed.
+All the necessities were there in the kitchen (2 pots, 2 pans, cutlery, glasses and plates).
+They received us (for an extra payment) at the appartement itself. Which came in very handy as we arrived at 23:45h.
+Cheapest (decent) option.
+There were towels to use
Minus:
-Streetnoise, if you're not used to living against the streetside and its noise; you may have trouble falling asleep.
-Distance to center is a good walk, as Porto is built on a lot of slopes it was tougher than tought. If you are a healthy person no problem. Otherwise, if you have problems with your foot or somekind, it's a difficult city. (there is a metro station nearby, so you can use that)