Apartment is small but very well decorated and clean. I stayed there with my wife and 10-year old daughter. I would say we fit well, maybe 4 people (2 adults, 2 children) would be the limit.
Kitchen is equipped and useful.
Beware the apartment is about 150m into a hill with rock pavement. We were carrying 2 large bags so it was a bit difficult. Taxis don't know the exact location since it's a pedrestrian only street. Ask them to drop you at Museu do Fado and then walk uphill.
There was some noise at night, particularly a neighbor discussing with his wife at midnight (two nights in a row) and eventually people walking up or down the stairs in the building. You can hear some noise from the street but nothing so bad. You can even hear some fado from a nearby tasca. Some neighboor in the same building smokes and sometimes you can feel the smell, specially in the stairs.
I would recommend the place to young couples, travelers with backpacks and similar. I would not recommend to people with walking issues or disabilities, or with large bags with small wheels like ours.
I really liked the kitchen - fridge, stove, oven, microwave, toaster, coffee machine, plates, tableware, etc. Very good! There's also a washer/dryer machine.
Bathroom was clean and also had soap, shampoo, etc. Clean towels, linen, etc.
Apartment could be hot in the summer (no AC, I believe). At this time late September temperature was fine.