I stayed at this lovely apartment for 6 nights with a group of 6 friends in our late twenties. It was absolutely perfect for a group. The booking and check-in process was seamless, and each time I sent a message I received a response within moments.
The kitchen is well-equipped for cooking. The bathrooms have great water pressure and are brand-new. The beds are all very comfortable and we had plenty of space. There was no street sound from the bedrooms, so even though it's across the street from the Mercado Bolhao, there was no disturbance.
It was nice to have 4 keys for the apartment so we could split up to go sight-seeing.
The apartment is a few blocks from Sao Bento train station, which was great for our day trip to Lisbon.
It is also within an easy walk to several different mini-neighborhoods with nice restaurant and nightlife options. Less than 10 minutes to the Clerigos tower and a lazy 15-minute walk to the Ribeira.
You couldn't ask for a more perfect location, and a more comfortable home base while you're exploring Porto!