We stayed with two Girls and had a great time ! Joses Mom is a lovely Lady, very sweet. Jose was really fast in answering our texts and Messages.
The closest beach is about 2 minutes away, but not too pretty. Another 2 Minute walk will take you to a way prettier one. Estoril itself is not that exiting, but Cascais is also in a 3km Walking distance or 6 mins by Train, which costs only 1,25€.
The Apartment itself was clean and spacious, although I would not want to stay there with 6 People. Great to have two seperate bathrooms, both with showers so we could save a lot of time.