Neighborhood was cute, very European. Lots of cafes, bars, restaurants on the same street only a block or two away. Felt safe and was very pretty. Sonia was helpful and accommodating. My flight was such that I didn't really get much sleep the night I traveled to Lisbon and Sonia helped out by allowing me to check in a bit earlier so I didn't have to try to kill several hours on one hour of sleep walking around with my luggage. She gave me a map and some helpful advice about the neighborhood, Lisbon, and the apartment that I followed. There was a washing machine and detergent in the apartment, but no dryer, but there is a clothesline outside the window and a bag full of clothespins with which to pin your clothes, in an area with a ceiling (so sheltered from rain).
The only thing I didn't love about this apartment is the shower. It's an old building so to turn the hot water on at any of the faucets you turn the handle to 'hot' and all the way up, and that turns on the hot water burner. The problem is that this shuts off again after a couple minutes. So for most purposes this isn't an issue, but unless you can finish your shower in 90 seconds, you have to keep turning the shower on and off to not get pelted by ice water. So, that was kind of a pain. But everything else about the apartment was great.
It's small but not cramped, fine for one or two people. It was clean and had enough toilet paper, paper towels, towels, sheets, napkins, pillows, soap, kitchenware, and detergent at the ready. Very easy to pretty much completely shut out light and noise if you need to, or get some fresh air and light in when you want it. Wifi worked very well, password is printed on the router and also on some art hanging on the wall.
Location is on the edge of Mouraria, so a short walk to there, Alfama, Praça do Comércio, Rossio Square, São Jorge castle, and Baixa. The apartment is on the side of a hill. I never tried to take a cab or Uber (Lisbon is very walkable and public transit is much cheaper) so I don't know if all vehicles all go all the way up the street (cars do drive by there, though). So if you're walking to the apartment from the train you will be walking up a hill or up several staircases to get to the street depending on where you're coming from, so if you have heavy luggage or a physical impairment you may struggle with this. I'm 35 and not in the best shape and I handled it okay, but if you have an injury or physical disability this might be an issue you need to consider just in case your cab/Uber doesn't go there for some reason (again, they probably will as I saw many cars drive by but I don't know for sure).
Overall it was an ideal home base for my 4-day trip to Lisbon alone, aside from the shower experience. Sonia is a wonderful host and I'd definitely recommend staying there if you don't mind the short "hike" up and the hot water situation because everything else about it was great.