Our stay in Marta's apartment was very comfortable. I especially liked the decorations and pictures, which provided a cosy and like-at-home atmosphere. The location is great, the metro and bus station "Marques de Pombal" is just two minutes away, same for the supermarket.
We met Marta during check-in, she was very kind and the communication super fast.
It was a little noisy at night (thin walls / air conditioning from neighbours?), so if you're a very light sleeper this might bother you.
Except for that, total recommendation! :-)