There's so much I can say about R, so I will try and make it short. Firstly, it is an open source tool, which means you can download it for free (for non-commercial purposes)! There are licensing charges for enterprises but it isn't terribly expensive, especially for all that it can do. There are so many add-ons/packages (ggplot2, dplyr, etc.) that allow you to perform specific tasks with ease. R really takes data analysis to the next level and allow you to combine that with enhanced data visualization to know only interpret your data, but display it to your audience.

This is a free Integrated Development Environment, which makes is quicker and easier to program in R. I find it much cleaner and easier to use than the native R console.

I like the user interface, where I can have multiple windows open showing the plots I am making while still being able to manipulate the code.