We stayed at Andre's place for three days and we had a very nice time. The apartment is in a quiet area of Estoril with a supermarket and a couple of cafes within walking distance. The station to catch a train to Lisbon is a short 10-minute walk away.
The apartment is on the 3rd floor and building does not have a lift. So, if you travel with heavy luggage like we did, it will take some effort to navigate the stairs. The place itself was nice and comfortable with everything you need for a short stay.
I should mention that the apartment does not have an AC. Depending on the time of year, this may not be an issue. We were there in the summer and the afternoons were a little warm.
All in all, a nice place to stay for a few days. If you're heading to Estoril, check out Andre's place.