It’s good place to start sightseeing Lisbon. In the neighbourhood are many shops, restaurants etc. It is very close to main square. It is good point to take bus, tram or metro.
Flat is located very close to tram line, so you should be aware that the noise will be high. For me it wasn’t a problem because I expected that.
In my opinion it is good place for people who likes spend a lot in old part of the city. Contact and check-in is excellent.