I would highly recommend this apartment for groups. The two double bedrooms have their own balconies and en-suite bathrooms. There is a third bathroom in the hallway, with hand basin but no shower. The living and dining areas are large and comfortable. The kitchen is very well equipped. There is a door between the bedrooms and the corridor, so that it is possible to sleep even if others are chatting in the living room.
All of the rooms have shutters on the windows so that you won't be woken by the sun if you don't want to be :-)
There was a 'closed-in' balcony too, where you could hang washing. There was so much sun that the washing dried very quickly.
There was only one drawback, but it would not stop me from going back there if I were in Porto again - the street outside is very busy and loud so it would be difficult to sleep with open windows. I am noise-sensitive so used earplugs as well (my friends didn't).
Joana was a fantastic hostess, extremely helpful and flexible and answered all emails very quickly. You won't find better, in my opinion.
All in all, a great experience. And the city of Porto is beautiful too!