I'm glad to see the quick convergence on Python. I've evaluated Python every ~2 years since 2006 for "data science" tasks (machine learning, statistics, data munging, and visualization). I'd argue that Python only properly covered this full data science stack 1.5-2 years ago. R covered this stack adequately probably around 2011-2012. Matlab had this before 2005.
What makes Python a superior language to Matlab and R is the ease of software development. It's an easy, pleasant language to work in, and I trust it for production tasks (I've written production R code and it's fairly hard to read and fragile).
What's even better is data science is moving 100% into Python 3 (from 2) by 2020:
http://www.python3statement.org/