I have never heard of that agency but there are so many now.

The area is fine - right in Recoleta, a block away from the cemetery and a central location from which to explore the rest of the city. Av. Las Heras is very busy with traffic and noisy colectivos (buses) 24/7 but if I'm looking at the same apartment as you it seems to be rear-facing so you shouldn't have a problem with the noise in that particular flat.