We stayed at the apartment for a week, including carnaval weekend. It's located very close to the bottom of the Escadaria Selarón - the famous Lapa steps. Whilst the are was pretty raucous on the Friday night, it was suprisingly quiet for the remainder of our stay.
Due to the wealth of things to do during our stay (true even outside of carnaval time) we didn't spend a great deal of time in the apartment but it served us well.
You're a 5 minute walk from the Lapa arches in one direction, and 5 minutes from Gloria metro subway station in the other.
Whilst I did not meet Márcio, he provided all the necessary information prior to check in and made sure everything was ok during our stay.