For a statistician, R has a variety of packages that are unavailable in Python. RStudio is a very easy to use cross platform dev environment. With a different R kernel, you can take advantage of multiple cores.
I use both (cut-paste monkey!). There seems to be a bit more magic with R, less code. Shiny is pretty cool too.
btw - shinyproxy package was compromised recently - check your download hashes :(
Tight integration with Rcpp also makes it very easy to speed up calculations when performance becomes an issue.
Also Python is not a "statistician" language so the adoption there is very slow.