It's a supercharged version of bash that works with Windows, but instead of piping character-only data, it can pipe structured data between commands in the form of objects. The reason I ask is because, while it adds a ton of flexibility to shell scripting (to the point where I consider it to be a language), it is also quite complex.
The benefit of shell scripting is that it is simple enough to have as a tertiary language that you can pickup and use after a six month hiatus. Once you get into more powerful language territory, there are a lot more components to memorize and it becomes difficult (for me at least) to keep those idioms in my head if they go unused for months.