I agree with the above about R. But as regards to reliability, I would prefer SAS to R, even though I hate SAS even more than R. Yes, R has lots and lots of features, good documentation, better libraries than any other out there. But sometimes I find discrepancies between R and SAS in performing the same operations, and when I test which is right SAS always seems to win. That is to say that R as an open source platform has the same problems open source platforms tend to have -- buggy code, sometimes inconsistent or barely-there documentation. Vendor-supported software like SAS does have a quality advantage.
Also, Matlab / Octave rocks when it comes to matrix manipulation. It beats R hands down in working with matrices.