I stayed with Matías for 4 weeks and was really happy with everything. The apartment is spacious and offers a lot of places to do some work, the room big with its own desk, lots of storage space and a large window front to let in all the sunlight (if wanted, otherwise just put down the blinds). A cleaning lady comes once a week so everything is clean and tidy.
The neighbourhood is pretty with lots of green including the botanic garden, japanese garden and various parks in walking distance. There's a metro station 5-10 mins away and bus lines even closer, so it's easy to get around.
Matías is a nice and interesting guy who takes care of all possible concerns which in my case weren't many. I was working during my stay with him so he made an extra effort to make sure the WiFi was solid which is not always the case in Argentina.
Oh, and an extra star for the pizza place right downstairs!