I've stayed at Mexico City Hostel at least four or five times in the last few years. Here are some of my experiences:
1. The staff are usually friendly and helpful.
2. Breakfast is good - usually eggs, toast, coffee, juice, yogurt, and fruit.
1. Eight person dorm can get a bit smelly due to lack of an external window. It has windows that open into the middle atrium of the hostel which is makes it bearable.
2. In my experience the folks I've met here are not as friendly as at other hostals. It may be due to the fact that there are more people here than a usual hostal. But overall, I haven't connected with people here as quickly as in most other hostals.