Sunday brunch here is fantastic - it's a buffet of gourmet Mexican cuisine. You can eat inside or on the patio overlooking the valley in which are gardens and fountains. Just beyond the fence surrounding the hotel is a park so the green seems to go on forever.
The service is fantastically attentive and after brunch you can walk around the grounds - definitely worth a visit.
If you go on the Biblioteca's house tour La Puerticita provides a free van from the last house to the hotel for the brunch. The hotel is on a hill in a residential neighborhood - rather out of the way - so if you are unfamiliar with the city or not enjoying walking on cobblestones (or late at night since the streets are not lighted) you should take a cab. When you leave, if the van driver is still on duty, he will drive you back to the main part of town or to your hotel, whichever is closest.