1. Piping object instead of string. This is what Powershell inspire other new generation shells.

2. .NET integration

3. Maintained by a large company. Extensively used in commercial.

To elaborate on "piping object instead of a string" Powershell just has lots of quality-of-life features. I think the fundamental problem these days with the shell "do one thing and do it well" concept is that nothing in traditional posix outputs structured data, so every single command and script is a mess of cobbled-together ad hoc parsers and sorters. In Powershell all the builtins emit structured data so there's no need to, for example, write a regex to parse out the mtime of a file. You just do `$file.LastWriteTime`.