We stayed in the apartment for a week with our friends. The place is great! It's spacious, with a nicely equipped kitchen, big living room, and comfortable bedrooms.
Diego was very helpful, gave us a quick overview of the city and some very useful tips. On top of that, he was able to accomodate our flight schedule in terms of check-in/check-out times.
As for location, Recoleta is a great neighborhood, lots of restaurants and cafes in the area to fit different tastes.
Overall, highly recommend visiting Buenos Aires and staying at this apartment.