We spent a good week in this flat with our two kids and my parents. The flat is very big and very beautifull. There a huge living room and a big table for nice meal in family. There's a lot of toys for the kids and arts and travel books for adults. Mariano and his brother were very nice. Victor, his brother welcomed us and he has to wait for us late in the night because our flight was delayed. Mariano gave us lots of tips and adresses for nice things to do in Buenos Aires, with kids or where we can find bread.
There were a problem with the cleaning as the personn who were supposed to do it was not able to came, but Mariano warn us and we accomodate with it.
Also, the flat is not in San Telmo, but in San Cristobal.