There's a common joke in the R community, which is to end any advice you give with something along the lines of:
...and if you vectorise wherever possible, rely on primitive functions as much as you're able, and pay close attention to memory limits and non-primitive objects, you'll be going almost as fast as someone who doesn't know what they're doing but has Python.
Python is just faster than R. This isn't shocking - it has a much wider developer community, much fewer dependencies, and was created at a later date. It's also not insulting to R: R is not designed to be a speedy language. It's designed to be a language that can do a vast array of things to data, in a highly vectorised fashion, and it does that job wonderfully - it just turns out that us useR's aren't satisfied by that sometimes.
So, a lot of people depend on Python for things that need speed, or more generalised computing tools (Python has a lot of libraries for common and complex tasks), me included - I've gone so far as to build a connector into my standard utilities package. But I'm still an R nerd at heart.
That's why I was so pleased to discover that RStudio, the standard R IDE, actually has *drumroll*....
...a stylesheet for Python. It handles the reserved words and syntax, and even the indentation! It's actually more of a pleasure to write Python in this out of the box than it is to write it in Sublime, which...has a mixed record of compatibility and indentation handling on Xubuntu.
I'm still trying to work out if I'm more pleased, or amused that RStudio's devs built in support for R's main competitor/partner in a tacit admission that it has a role to play. But I'm going to go for "pleased".