There are several advantages to using R. Commonly billed as "the language of statistical computing", R offers built-in facilities for dealing with many of the basic operations of uncertainty quantification (e.g. random sampling from a variety of distributions). R's nature as an open source language offers a couple more advantages. First, it's free! There's much to be said for a language that doesn't require thousands of dollars of yearly payments, especially as your company builds a database of legacy scripts. Second, an open source scripting language allows for a greater degree of inter-institutional collaboration, especially when that scripting language is already in common use, as R is. The field of V&V&UQ is still in its relative infancy. For the next few years at least, cooperation in overcoming the technical challenges of V&V&UQ will take priority over competition between V&V&UQ specialists. Whatever your field, you will likely find the growing body of script libraries offered by your "competitors" to be a great help in your endeavors to quantify uncertainty and mitigate risk.