Mariana's place is great, better than expected. The location is truly awesome, walking distance from bars, restaurants, public transportation and anything you need, really. The place is spacious and looks renovated, despite being an old building. The stairs were quite steep and narrow, though, so keep that in mind especially if you have any mobility issues, could be challenging to go up/downstairs.
We just had one problem with the washing machine which wasnt working, but Mariana was very helpful and sent someone to fix it. We ended up taking our laudry to a laundromat just a couple minutes walk away from the place, though.
WiFi was fast, comfortable beds and well equipped kitchen. Only thing we missed was a regular coffee maker (there was an electric "pod" operated coffee maker with plenty of coffee pods, though, so no big deal.
Overall recommended to anyone going to Lisbon!