We had a great time at Marcos' place. We were a family group of six and the apartment was ideal: spacious and clean.
Marcos was a great guy: cheerful and very helpful. He was there when we arrived in pouring rain (a tip when arriving at Rio Airport: you can of course take a taxi, which is faster, but the airport bus - premium auto ônibus- will drop you off on the doorstep if you ask the driver). Later he checked whether everything was ok, which it definitely was, and it was no problem that some people in our group had to check out earlier because of different flights home. Great!
From the apartment, Leblon, Ipanema and Copacabana are all within easy reach - if you like walking you can even walk into Leblon from the house, there is a footpath along the Avenida Niemeyer. Traffic in Rio is often stuck, so by bus relatively short distances may take longer than you think.
All in all we had a great time at a great place!