We (me & my girlfriend) stayed in Maria's apartment a couple of days and had a really good time. First of all it was a pleasant place to hang out, lots of natural light, tasteful interior, a beautiful view (from floor to ceiling!) towards the garden. For working (or anything else) the table in the winter-garden is perfect — internet is quick as well.
Shower, bath & kitchen are well equipped and the bed "cave" is really cozy. In the night it was very quiet.
We had the chance to get a little tour of the house as Maria is an architect and we were interested in that and also the other rooms she rents out are super nice, each one has it's own charm and features.
The location of the house is central and at walking distance to lots of shops, restaurant and the river.

Maria was a great host, we always had good and prompt communication and she gave us some tips about Porto as well.
We'll definitely be back.