Positive sides: Flat is comfortable, modern and well decorated, looking out on to a traffic-free square. Really in the city centre, at the top of the hill(s), close to Trindade station (metro from airport), very close to everything. It is in the quiet and peaceful neighbourhood. We loved the local area, very un-touristy, in a city in February which felt unhurried. We slept well on a very comfy bed.
Negative sides: There was a problem with an unpleasant odour from the bathroom and the electrical installations don't really work when you turn on the heating, TV and bathroom light. These appear more an issue during a longer stay.
All in all a great stay in a fantastic city - more to do on a subsequent visit.