Querysets on views or on Model Managers DJANGO
According to the Django idioms want to add some advice that can be useful:

model managers it's a place for most common queries, not for all queries. Managers describe basic methods for working with models. If you have a widely-used logic for your model with queryset - put it to the manager's method. For example, my users split by domains, so I want to get the user by name and domain, so add the get_by_name_and_domain method to the user model manager. Also, you can access your model by the model attribute in the manager.
models are the part of MTV (Model-View-Template) model on Django and the main purpose of the 'model' itself is to describe db-object but not related business logic. So put your custom queries to views and remember about DRY principle.
Some days ago a guy explained me that on ruby on rails the queries are done on models. Because it gets already saved at your data before be requested on views and the query.
By the way I've learned and had been working until now, I'm setting the query on views.py and passing, through a context variable. So I started to read about Model.Manager and still didn't find a answer to which way is better:

queries made on views
queries made by simple functions on models
queries made on models.Manager class for each model