This is a great hostel, in a wonderful location (top of Bairro Alto, seconds from Restauradores Square, this is premium Lisboa).

Big custom made bunks with privacy curtains, good secure storage for your personal things, no need for padlocks, proper room and outside door security, sufficient bathrooms, a really well managed policy on keeping the late night noise and lighting down so sleepers can sleep, which includes 24/7 staff presence. Free breakfast, free tea during the day, good background music not too loud, nice sitting room for a genuine communal experience. No bar (good) but occasional sangria and shared dinner nights, free walking tours daily. Can't fault it, I won't go anywhere else in Lisbon now, and I've stayed in three other hostels in this city before.