Fledeskum

One of the factors I considered when I switched jobs earlier this year was that the new place has a policy of devoting 2 months a year to refactoring :)

Most of the gain was from actual logic, if there had been only models & controllers we wouldn't have seen any major benefits. But there was a lot of IoC with the customary mountains of rather pointless interfaces, an "admin" of sorts & a "messaging" queue running tasks. Most of the POJO data classes ended up being replaced by Python's built in dictionary. Basically the mixture of Python's stdlib, the language ecosystem & Django's got rid of most of our code. In the cases where we couldn't reuse anything from anywhere, something like a business logic class would normally shrink by 2/3. And the frontend was not JS heavy so that factors in.

I hadn't started when the decision to go Django instead of Rails was made (Rails & .NET MVC were also considered) but I've been told it came down to a number of things:

* This is in Europe, generally Ruby is not used very much over here, Python has been used in some shape or form in every company I've have experience of but I've only seen Ruby recently and then mostly for Chef or Puppet.

* Lack of explicit imports did not work in Ruby's favour.

* If needed numpy & scipy don't have a analogue in the Ruby ecosystem.

* General negativity towards the religious zeal permeating through the Rails community.

The company I work for (which would qualify as an enterprise by any standards) decided to switch over to Django almost 3 years ago, rewriting our existing Java infrastructure on a project-to-project basis. The reasoning was primarily two-fold, we'd begun to have trouble recruiting good new talent interested in working with Spring/Java and we felt that for what we were doing, Java was not the strongest technology choice anymore (not like it was 10 years ago).

Last year, we switched a 55k loc Spring MVC (with JAX-RS for the json api) over to Django (using tastypie for the api side and celery for offline tasks). The result ended up being little over 8k loc of Python. Closing a ticket has gone from taking on average around 5 days to a little over 4 hours. That was the third project we ported over, the others having had similar success. YMMV.