We (couple, m, f) stayed in the flat with our 4yr old for 3 nights end of May.
The location of the flat is pretty much perfect if you want to explore the city. Metro and tram are 5 min away, as well as several nice restaurants. The street itself is not a party and pub street but the adjacent streets are and there is a restaurant next door, so while the flat is not super noisy, the 2 bedrooms on the street side are not quiet (ear plugs are advisable). The 3rd bedroom is located in the back and is quiet if you close the windows in the first 2 bedrooms. As in most Lisbon houses, everything is rather narrow, i.p. the bathroom (which is, as said, just typical and not a flaw of the flat). If you come with a baby stroller (as we did), expect some uphill pushing on old cobble stones (which is also rather typical for Lisbon).
Paula and Zita decorated and renovated the flat very nicely - it's a bit hipster style but cosy and not overdone. The pictures show correctly what you get.
Paula and Zita are extremely helpful. Though we have not met them in person, they responded very quickly to any questions we had and could even help finding a bike rental with children seats. Also, as we had a night flight back, they let us store our luggage until late afternoon, which was very helpful.