We had an absolutely amazing time in Lisbon!
We didn't see Mariana very much, but when we needed something, we knew we could always ask. Everything was so well organised! The apartment was also really clean and the best thing might even be the location! The steep stairs/hills you have to walk to get there are really quite tiring, but we were warned for that, and it is absolutely to be expected with an apartment that is so much in the city centre of Lisbon. Almost every major site was within fifteen/twenty minutes walk, we barely ever used public transport!
We think the only downside was that the mattresses were a little thin and uncomfortable, but we were so exhausted every night that we barely noticed ;)
We would definitely recommend staying here.