Excellent stay! The flat is perfectly located in a nice part of Palermo - very close to the Plaza Italia and within easy reach of good restaurants and supermarkets. The view was wonderful, especially from the balcony at sunset. The pool was nice and warm. Everything was clean and the process was easy from start-to-finish. We had a lovely time in Buenos Aires and a lot of that was due to picking the right apartment.
Perhaps most importantly, the service was 6-star fantastic - if something stops working, or if you accidentally lock yourselves out with the key in the door, or if you want to check in early after a flight change, you're treated as a top priority, and with perfect communication throughout. Special thanks to Andres and Marcelo for all their help!
Only thing not quite five-star was the bathroom - occasionally there was a bit of a smell, and the shower pressure was average. However, this was not a big problem and did not take anything away from our enjoyment of the stay.