Things we enjoyed: location - perfect for San Telmo and with access to public transit; the co-host Hernan was warm, kind, and very patient and helpful; washing machine is a huge plus; spacious.
Things that were disappointing: the quality of the furniture and space in general differs from the photos (worn and stained rather than posh); buttons to ring the apartment are mis-wired and we had no way of letting the host know that we arrived; building is very loud (especially on the weekend); the shower has very little water pressure and in order to have a hot shower the kitchen faucet must also be running the entire length of the shower.
Bottom line: Overall our stay was ok, but I would choose to pay a bit more for a situation that worked better for us.