Some advantages of R over Excel:
- R is a scripting language, which allows to record a data manipulation script once and reuse it multiple times.
- R, as a [scripting] programming language is much more flexible than very limited Excel's GUI. In fact, R has become a de facto statistical programming environment, which delivers most recent statistical techniques.
- R can handle much bigger data sets, even out of memory with the help of extra packages.
- R is fast with the help of
data.table, and fast and very flexible with the help of
- Community, literature, and existing knowledge base on internet/stackoverlflow.
- R has a superb quality, easy to learn graphing libraries like
ggplot2 and many special case others
Advantages of R over SPSS/SAS:
- Free (open source).
- Versatility of statistical methods (it should be noted here, that at least SAS, in recognition of R's speed of statistical innovation, provides interface to R)
Having said all that, think twice before investing into R as compared to other more modern scripting languages like Python (or Julia)