The apartment is rather small and not extremely comfortable – but it is bright and in an amazing location, so if you plan to spend a lot of time exploring Buenos Aires we can definitely recommend it!
We left the apartment cleaner than we found it – wiped every shelf and drawer before we put our things in and washed every spoon and pot in the kitchen before we dared to use them. We weren't too happy about it but I guess these things depend on the guests before you, too...
Note that you will need to speak some Spanish for the check-in – you'll have to coordinate with a neighbor and she was very kind but doesn't speak English.