Despite constantly reading on this website that R is bad or wrong, I somehow manage to get all of my data work done quicker and with fewer headaches than excel, sas, or Python.
These probably shouldn’t matter but did for me. FWIW the statistical offering was fantastic.
I'm sure it is poorly designed from a computer science perspective, but there is no programming language out there which makes it so easy to run any model under the sun as does R.
In Python’s case, the language isn’t bad, but the implementation is horrible for performance. It sits on the back of lots of fast C/Fortran/whatever code, and polished the (relative) turd a lot, making the end result quite usable, but the “sitting on top of part” also makes it hard to improve the performance of the implementation.
For both R and python the end result is good, but they still are local optima in the space of what is possible.