A problem with hosting Django on Python 3 on Heroku though is that you need to use something else (like s3) for staticfiles. Boto doesn't support python 3 yet, so you can't use the django-storages implementation. The Heroku documentation recommends using dj-static as an alternative to s3, but dj-static relies on a library that was last updated in 2009.

New Relic seems to support Python 3 now though, which is nice.