Overall Casa de la Tia Tere is a decent choice to stay in Oaxaca. Service was excellent, the rooms were very clean and having a pool to come back to at the end of the day was nice.
Bear in mind that most of the rooms have no windows that face the exterior, they only face the inner courtyard where breakfast is served. We were lucky that we faced the pool and we had small doorway that opened which let light and fresh air in. If we had a room that had no exterior window I don't think I would have enjoyed my stay as much. Also be warned, the beds are very hard.
The location is only a slight drawback, yes it is about a 10-12 minute walk to the Zocalo but really, it wasn't that bad. Some days we even did it three times. Walking back at night was fine too.More