There has been tension between the Python and R community, but not at all with the developers, i.e. feather development by both R's Hadley Wickham and Wes McKinley. Python and R are great tools, but the Python community tends to call R garbage and believes that Python has over taken R which is actually not true. R has really grown and is still the number one Open Source language in the domain and I think R has more resources behind it than Python.

http://r4stats.com/articles/popularity/

R has actually already surpassed Matlab. Now R has some funky sides to it (Which you don't need to use) and R also has many people who were not good at programming making horrible examples. It surprised me how functional R is and there is a lot of Scheme in the under belly. The tools and libraries are just getting better and better.

R in the past 4 years has really become amazing. I left Python for R and it has been an amazing ride for me with the Hadleyverse of libraries. Millions has been invested into R with Microsoft even making it a part of SQL Server and Azure after buying R Revolutions. The tools that have been coming out are amazing.

Julia has been a promise on the horizon which I haven't had need of. For my workflow R has been dead on pleasure to use and my data sets are not so large that I need it. I also could use R with Spark if that ever becomes an issue.