I stayed at Judith's place for more than a month, as my workplace was near the apartment. The apartment is located in Downtown Buenos Aires, which is a very good starting point for various tours. This area is busy during the day and quiet at night. Bars and restaurants are within walking distance (about 10 blocks to Puerto Madero and fewer blocks to several restaurants). Public transport is readily available with a huge variety of choices (very near to Retiro train station and with a lot of buses nearby). Cabs are also available in this area at any time of the day. The apartment itself was a good place to stay over a long period of time as it looks more as a regular place than a hotel room - and it has appliances you won't find in a hotel room.
The host was always available and had a very quick response rate. She also tried to promptly solve issues that came up.
Overall, a good choice at a fair price.