A group of 10 of us stayed Friday to Monday at the apartment. We had an absolute blast. Although hilly, the apartment is pretty close to the bars of Bairro Alto.
Metro stop is only a 5 min walk.
Like most places in Lisbon, the apartment rule was no noise after 10pm until 8pm. Any noise in the apartment seems to echo, as it is so massive, so you really need to be quiet when returning from a late night out.
Miguel met us at the apartment a little before the check in time which was great. He gave us good advice about where to go and how use things in the apartment.
Any more than 10 people would maybe make the apartment cramped, but it depends what you want the apartment for.
Highly recommend the apartment.