The apartment is very well located - in the historic centre, nearby the São Bento train station. It is a small studio, with all the essentials you might need if you are the kind of traveller that spends most of your time outside rather than in the accomodations. It might be a bit noisy sometimes during the night, but as I said, if you have spent the whole day walking and exploring, you won't mind it at all.
It is clean and has the kitchen with appliances, which is very helpful.