We stayed for a little more than a month at the apartment. Here's a complete review:

Danilo is a very polite, welcoming and available host. He always reply on short notice, speaks English very well and will do his best to solve any problem. The apartment looks exactly like pictured, has lots of space and closets, a good kitchen and a laundry area. All the home appliances are in good shape. The internet is fast and stable. I worked full time for many days and had no problems whatsoever. The place is also really quiet despite being in a busy part of town. Speaking of which, it is a SUPERB location, right at the center at the city. The buses 152 and 39 will take you pretty much anywhere in the tourist circuit, and you can get those really near the building. The subway station is also 2 blocks away. Not to mention that the Recoleta neighborhood itself is a pleasant one.

But no place is perfect, so here's what can be improved:
There's only one AC/Heating unit, and it's located in the living room. Although you can turn it on and let the air flow into the bedroom, it's energy consuming and not very effective. We were lucky to have a mild winter, so this was mostly not a big deal. But in the colder days, it was quite cold outside of the blankets. The fact that the bedroom window's lock is not 100% functional doesn't help, since the cold air finds a way through the gaps. We also had some problems in the bathroom, that Danilo fixed, but the window is still not in a good shape and the sink is leaking a little. The 9AM checkout time is too early! This was my first AirBnb experience, but most hotels checkout time is around 11AM/12PM, which is more friendly to flight times.

All in all, a great experience. I'd stay there again and, for shorter trips, it's a no-brainer. For longer periods, It would be even better if Danilo could make the improvements I suggested!