As a minor rebuttal, I get sick of Flask because it is bring-your-own everything. Nothing I write will ever NeedToScale(TM) or be off the beaten path from the Django Way. No interest in plugging in an alternative template language, form validation, email library etc. When I get stuck in Django, I know someone else has experienced the exact same situation. With Flask, I have to pray to deity that Miguel Grinberg has written about a similar enough situation. The majority of documentation foregoes Flask Blueprints.