The apartment is huge and very clean. Perfect for a large group especially if you have kids. Location is convenient for exploring though we found out there are very few restaurants close by. You have to walk to the park (10-15 min walk) to find them.
Communication and check in were good, just call them about an hour before you arrive. The living room is huge and has enough table space for 10 people, nice views from there as well. Beds were confirtable. Extra blankets provided.
Please note the apartment does not have any central heating or a/c. During our stay the weather in Lisbon was in the 50s and 60s and the apartment was freezing. They only had two very weak air heaters which we left in the kids rooms (they only made marginal heat). We had to wear our jackets inside a lot of the time, which was not very convenient.
Other than that, we had a good stay.