The correct answer is: It Doesn't Matter.
In spite of this.
(A) The question gets asked.
(B) It gets answered. And people take their answers seriously. As if there are Profound Differences among programming languages.
Among Turing Complete programming languages there are few Profound Differences.
The pragmatic differences are the relative ease (or pain) of expressing specific algorithms or data structures.
This means that there's no easy, blanket, one-size-fits-all answer to such a silly question.
You can have some code (or data) which is painful in Java and less painful in Python.
You can also find an extension library that makes it much, much less painful.
This, alone, makes the question largely moot.
When it comes to a specific project, the question of the team's skills, the existing infrastructure, and any integration requirements are the driving considerations.
Because of this, an incumbent language has huge advantages.
If you've already got a dozen web sites in Java, there's no good reason to flip-flop between Java and Python.
If you're going to switch from some Java Framework to Django, however, you'd do this is part of a strategic commitment to drop Java and convert to Python.
To read the discussion, see LinkedIn Python Community. http://www.linkedin.com/groupItem?view=&gid=25827&type=member&item=5796513808700682243&qid=8612bee7-76e1-4a35-9c80-c163494191b0&trk=groups_most_popular-0-b-ttl&goback=%2Egmp_25827