Florence's flat is great for the price. Everything is recently renovated and the location is perfect for people visiting Lisbon who want to be in the center of everything and able to catch a train out of town in minutes. She has a thing going with the travel agency downstairs so they took care of us (they're all amazing btw).
We managed to squeeze in our family of five plus a baby, but it was tight and I wouldn't recommend it if you have the choice. Four + baby would have been much more manageable though.
Definitely noisy on the streets on the weekends. Also, the place is a rental and not someone's permanent home, so it is missing some things that you sometimes expect (drawers for your clothes, sharp knives, coffee pot no longer). It didn't take away from the experience though. I loved the spot and would stay there again.