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Some times R gets a bad deal. 
- R has come a long way and it is a powerful functional programming platform, with print ready visualization tool where you can do anything; the limit is your hard work and imagination
- R is a variation of S the free version when the original seed, S, became S + as a commercial product.
- You can do anything in R as much as you can do anything with C or C++
- R is continually supported by a large group of practitioners and you will get help for free
- One version of R become Revolution R with some special purpose packages which was sold as enterprise edition, another branch of R, and got bought out by Microsoft
- One of the rock stars of R is Hadley Wicham, who is continually making great contributions improving R
- For daily life of a data science practitioner, there is no pride in saying you do not know R, even if you know Python.
- Here is a copy of advanced R by Hadley Wickham:    (not sure it is truly free or someone leaked it out); I am buying the real book. - R BEATS PYTHON! R BEATS JULIA! ANYONE ELSE WANNA CHALLENGE R?
- It is neither humbling nor a pride statement to say that a data scientist says that he/she does not know R.   It is an important tool in a data scientist's tool box.
- Many complain about R that it is difficult; more complained about SAS and continue to do so, but SAS's power is well known. 
- War of languages 
Another war of languages about R/Python/Octave/Matlab/Julia - . One more:

- The minimalist approach for programming languages for a data scientist from my perspective is R/Python/SAS.   Until proven, do not waste your time.