I loved staying here; Nuno was a great host, funny and informative; and he's around fairly often, which I like, as I use AirBnB for contact with local people, not just 'a room'. As I don't speak Portuguese, it helped me that his English is so good. The flat is not posh, it's in an old building, but has everything you need with the bonuses of the great view and easy access to transport, attractions, cafes. It's literally a couple of minutes from Rossio. I was lucky enough to be there for the San Antonio festival, right in the heart of the music and street life.
The flat is up on the top floor (hence the great view) but if you don't like stairs or have a load of luggage, Lisbon might be a tricky destination in any case. It's hilly and the easiest way to most places is up lots of stairs.
The bed and room was good for one person, might be a bit small for two who like to spread out.