I was in Buenos Aires with my partner for an academic conference and tourism, and Jimena's place wonderfully fit all of our needs. It is very central to many of the places one would likely visit in BA. And for those areas that aren't quite walkable--such as Palermo--it's an easy taxi ride (Radio Taxi is particularly reliable for this).
The place itself is as advertised, marrying an older charm with some modern amenities. Although the sounds of the city billow up into the apartment during the night, it actually creates a kind-of pleasant background noise (though, if you're a very light sleeper, it may not be ideal). And for those new to the city, country, or continent (such as I was), it was very helpful to have such great doormen at the building. They were very kind and helpful even though my Spanish is incredibly rusty.
As a host, Jimena was great. In the apartment, she provides a thorough guide to the city, listing good restaurants, tourism spots, etc. And she was always very responsive when we communicated.
All in all, if you're looking to find a comfortable, charming place right in the heart of Buenos Aires, Jimena's apartment is a great fit!