Ari was communicative and friendly, although we didn't meet him in person he provided everything we needed in terms of communication. Our flight leaving Buenos Aires was at 11 at night and he let us check out late, even suggesting it himself.
The flat is very nice. Clean and spacious, comfortable bed, good wifi, great shower, very central. Has a kitchen if you want to use it, although there are a lot of good restaurants in the area so I wouldn't bother.
Stay here, well worth the price.

For people flying into Ezeiza airport - you can take the number 8 bus from the airport to Plaza de Mayo, then get the metro (Subte) from there to Plaza Italia, the nearest station. Price is a total of 10-11 pesos per person- less than one USD. It takes a fairly long time (2 hours instead of 45 minutes), but considering the price of taxis and buses, if you're travelling on a budget and not in a hurry it's worth it.
To do this, you need a Sube card, however you can just ask someone at the bus stop to pay for your ticket on their card and then give them the money for it.