I learned R but it seems that companies are much more interested in SAS experience. What are the advantages of SAS over R? 
I think there are several issues (in ascending order of possible validity):  


Tradition / habit: people are used to SAS, and don't want to have to learn something new.  (Making it more difficult, the way you think in SAS and R is different.)  This can apply to anyone who might have to send you code, or read / use your code, including managers and colleagues.  
Distrust of freeware: I've had several people say they aren't willing to accept results from R because you don't have a for-profit company vetting the code to ensure it gives correct results before it goes out to customers, lest they end up losing business.  
Big data: R performs operations with everything in memory, whereas SAS doesn't necessarily.  Thus, if your data approaches the limits of your memory, there will be problems.  


Personally, I only think #3 has any legitimate merit, although there are approaches to big data that have been developed with R.  The issues with #1 speak for themselves. I think #2 ignores several facts: there is some vetting that goes on with R, many of the main packages are written by some of the biggest names in statistics, and there have been studies that compare the accuracy of different statistical software & R has certainly been competitive. 
