The apartment itself is lovely, clean, and a good size. It was very warm when we were in Lisbon so we really appreciated that it had air conditioning. The bed was large and very comfortable and we appreciated that on each side of the bed there was a light, a shelf which acted as a nightstand and closet space.
Overall we found the apartment to be very nice and very comfortable.
The only minor complaint I would have is that the shower head doesn't really mount well to its wall holder so you really have to hold it while showering which is tricky since you're also explicitly told not to get water on the bathroom floor and there is no door to close the shower off from the rest of the bathroom. This wasn't a huge problem and the shower itself was nice and clean and had plenty of hot water, but it was a bit awkward and could be improved on.
As noted in the listing there is construction going on next door and it is loud. It wasn't a problem for us because we were out and about everyday and it was done by 6pm, but if that's the sort of thing that's going to bother you just be aware of it.
We chose the location because we wanted to be in the more historical part of the city, but do be aware that Lisbon is a very big city, so you may need to take public transit to get around a bit. That said we did a lot of walking and most of the city was easily accessible on foot from where we were.
Overall our stay was great and I'd definitely recommend it.