UNIX is a very powerful operating system which has been around for more than 30 years. Initially, it was primarily been used by industry and academia. However, since Linux, anyone can have a UNIX system installed on their computer. Having UNIX on your computer is like having an industry strength product. Much of the Internet still runs on UNIX.
Since UNIX has been in the academia for decades, much of its software is available for free. In addition, there is no shortage of blogs full of helpful comments.