We had a great stay at this apartment! We didn't meet Jony in person, but communication was very easy and there were maps and useful information in the apartment. It looks exactly as on the pictures and everything you need is there. The kitchen is fully equipped and there are also salt, pepper, oil, vinegar, ... which is perfect when you want to do some cooking.
Palermo Soho is very nice (and secure) with lots of restaurants and shops and it's not far from the studio. I can really recommend staying there, it's the perfect place if you want to stay in a nice neighbourhood and not in the center of Buenos Aires.
(That doesn't mean it's far away from the center - you can reach it easily by metro)