Summary: A large apartment in a "typical" non-tourist-oriented neighborhood that I found to be comfortable and convenient. I would not hesitate to stay again.
The apartment is surprisingly large. For this trip I was alone (during the coronavirus confinement, so I needed to spend a lot of time inside!), but I could easily see four people being comfortable here. In addition to being large, the kitchen is complete, with a full range, microwave, large refrigerator, and full-size oven. (I also found a nice range of basics: salt, sugar, spices, cooking oils.)
It is not in the heart of a tourist area, but I found the 20-30 minute walk to be refreshing (and providing a bit of exercise ascending and descending the hills). It seems to be typical of many neighborhoods in Lisbon that there are not many trees along the streets, which makes it seem a little stark to my American eyes, but the neighborhood offers views of the river and town that are interesting and expansive. There are a couple flights of stairs up to the apartment, so if that's a concern, you'll want to consider something else, but I'm no spring chicken, and I didn't find it onerous.