In my experience, there are a few things to consider here:
- What field you're going into
- What kinds of technology you believe you'll be working with
- What kinds of teams you believe you'll be working with
Field
This is a huge determiner. To my understanding, SAS is standard in finance, banking, some biostats, and other industries. R, on the other hand, is open source, free, and is receiving a lot of attention currently from Microsoft after their acquisition of Revolution Analytics.
Technology
Are you thinking you'll be at a large corporation or a small shop? Do you think you'll need to work with creating production ready algorithms or simply producing insights and analysis?
The reason this matters is that open source technology can often times be a bit easier to convert to production ready use. The cost of software can also be a barrier at smaller companies and may dictate what you are capable of using.
Collaboration with Other Teams
If you sit firmly on the business side, it's possible that everyone you work with may use SAS or may be comfortable with the outputs. In this case, you may not need to collaborate across any additional technology.
If you work with technology, however, it may be difficult to integrate SAS or proprietary solutions into other workflows. An example would be creating a real-time user scoring system. If you were able to program this into R or Python, you may be able to pass the code directly to a developer for implementation. This would be more difficult if a proprietary solution was involved.
Other Considerations
The analytics space is evolving rapidly. On top of the above, Python is coming out as a very popular technology for use in machine learning and data mining and pairs well with Spark as well as some other large data technology. A specific example of a library here would be scikit-learn.
Closing Thoughts/My Experience
I'm an R/Python user by experience, though I have some experience with SAS in school as well as in work. Generally, I've found the level of support with R and Python to be great - especially since they've started to rise in popularity. SAS has its uses and has definitely carved out piece of the industry for itself.
All in all, however - getting a solid base in statistical theory, programming (scripting), and understanding the application and value that analysis can provide will go a long way. The syntax between these tools is, generally, not worlds apart. SAS can be a bit strange compared to R and Python, but all of these tools generally have syntax which is fairly readable and is not difficult to adapt to another tool.