The apartment is well-appointed and in the middle of it all in Bairro Alto. The hosts are easy to communicate with and helped us with our transfers as well. Multiple dining choices are all within a few steps, and the hosts provide a number of recommendations as well. As others note, it can be loud at night, especially on the weekend, but closing the windows effectively mutes it.
Also, be aware that the apartment is a walkup on the 3rd Floor (4th by US measures). There is no elevator in the building but the stairs are wide and easy to navigate with luggage. Knowing where the public elevators are up to Bairro Alto after a long day makes the last 59 stairs to the apartment that much easier. :)
We enjoyed our stay and would happily stay again!