Great place!
I used to live in Ipanema. I know quite well the area: the apartment is in the best location!!
2mn walking distance to the main Ipanema subway station (where you can go directly towards Downtown or towards Barra).
1mn walking distance to a good supermarket.
1mn walking distance to my favorite laid-back coffee/lunch place in Ipanema: Cafe Felice
2mn walking distance to the beach!
Even though it is very Ipanema-central, and perfect also if you like street Carnaval (middle of the action :)), it is quiet, as it does not have a direct exposition to the street.
Note that the apartment does not have any view. But it did not bother us, direct sunlight is not always welcome in extremely-hot-Rio, and it's the price to pay for the quietness.
The apartment in itself is great too. There is everything you need. You can cook, log on easily to the internet, watch TV, and mostly you can sleep... very very well! The king size bed is soooo good, slept like a baby :)
Felipe, the host, is a very nice person. He is very helpful and replies very fast via AirBnB or SMS to any inquiries you may have.
Checkin/checkout is very smooth and easy. Doormen are very sympathetic and there 24-hours.
One big plus for us was the parking space inside the building. And I also looked forward to use the available bicycles but unfortunately it was too hot outside. For anyone who does not know Ipanema and the surroundings, you can do great bicycle trips from there, there is a cycle path along the beaches and also around Lagoa.
To summarize: highly recommended!