I loved staying at Joni's place and would do it again when I'm back in Buenos Aires.
The location was just right for me - close enough to Palermo and easy access to transit. There are a couple of great coffee shops and empanada places nearby as well.
The apartment itself is really new and has got amazing amenities including a washing machine.
Joni and Geri went out of their way to ensure that I could check-in and check out at odd hours to catch my flights.
Overall, I would highly recommend staying at Joni's place!