We stayed here for two months and loved it.
The place is much bigger and nicer than the pictures suggest, and it had everything we needed during our stay (including 100Mbps internet).
It's also relatively old, which has pros and cons: while some things could use some renovation, the age adds to the apartment's character. It's like living in a museum with all the art and incredible tiny details. So if you're looking for an ultra-modern apartment, this probably wouldn't be the right choice, but if you want to stay at a truly unique place with lots of character, this is it.
The location is perfect, with everything you may need within walking distance (I'd argue that Recoletta is the best neighborhood in Buenos Aires). The communication with Carlos and his daughter was flawless, and they were very helpful.
Highly recommend!