The apartment is very well located and connected to main attractions and areas in Lisbon. You will be sharing the ap with two other rooms, that is 2-4 more people. The room we rented (B) is not too big but it can house two.
We had several issues with the common bathroom hygiene. This was other guests' responsability, of course, and not the hosts'. We addressed the issue and they committed to speak to the other tenants. Still, there's a lot of people coming in and out so it's hard to keep a standard.
We were there in winter an the flat was very cold. An electric duvet was provided for the bed, but the flat and room don't have any heating (probably a general rule for Lisbon apartments though).
In short: we were there for a week and found it OK, but we would only recommend it for a briefer stay.