SUMMARY: [R] Comparison of SAS & R/Splus
In case you are interested in the topic of software numerical accuracy, this is quite informative. I do not know how Stata fares, but I suspect it does very well because the product is semi-open and continuously tested. I am sure R is still on top of the game today.
Screenshot from the Variables application for Mac OS X, offered at a very low price on the Mac App Store. I like the idea very much, especially since regression models are integrated to the software.