Even though we never met Marcos (because he was away during our 4-day stay), we still had a nice time at his apartment. Because we didn't meet Marcos and because the two other rooms were full of guests while we were there, it felt more like we were staying in a hotel than in someone's home.
The location is ideal for the beach but the neighborhood is a bit pricey, it was hard for us to find meals in our price-range in Leblon. It is, however, a very safe neighborhood and the building has doormen 24/7.
The apartment is very spacious, and the bathroom is very nice, with a really lovely shower.
The biggest problem we had was the incredibly creaky bed! Unfortunately, it would often wake us up at night.
Despite this, we did have a very nice stay at Marcos' place, and when I accidentally left something in the apartment Marcos was great about helping me go back and get it later that day after I had already checked out.
Thanks, Marcos!