Joana (she's the artist created the artwork in the apartment) was helpful and easy to communicate with.
The apartment is in an almost perfect location. Walking distance to the Duero river, the Sao Bento Station, the University district with the famous Libraria Letto. The port wine district can easily be reached by a 10-15 minutes walk or a short tram (yellow line D) and cable car ride. I'd recommend the walk over the old iron bridge, the view is amazing.
Once the new pink line of the Metro is finished, there will be even a metro stop just outside the apartment (by 2023 or 2024). Howerver, Sao Bento is just a 2-3 minutes walk away. Journey from/to the airport using the Metro takes about 50 minutes.
The apartment itself was just recently renewed. It is clean, with stylish furniture and a walk-in wardrobe / dressing niche. There's basic cooking equipment with a 2 field boiler plate (induction!) which was suitable to cook fresh seafood from the local seafood market. The coffee machine (Nespresso) is helpful in the morning. There's also a microwave and a toaster (which we didn't use).
I can fully recommend the apartment and the host.