I currently live in London, but I was a local in Buenos Aires for many years. As such, I can confidently say that this is located in one of the best areas of the city. "Bajo Belgrano" is just below "Barrancas", and is very residencial and probably as safe as Buenos Aires can be.
There were a couple of things that needed upkeep in the apartment and it could use a clean up as it seems no one has done one in a while. There was dust everywhere and a lot of the surfaces were visibly dirty. The provided towles weren't in great shape and they probably need to be replaced.
Having said that, Paula is a great host, very flexible and easy to get in touch with.
Overall it was a good stay.