Path Finder is one of many Finder replacement tools that are available, but it could be better regarded as a greatly enhance version of OS X's built in folder navigation tool. The program very closely resembles the look of Finder, but it has a number of extra buttons and toolbar that provide access to additional features and options.
One of the simplest, but most useful, features of Path Finder is the dual pane view that makes it easy to copy and move files and folders from one location to another. Web browser style tabs can be used to quickly jump from one location to another and frequently used folders can be bookmarked for easy access.
Comprehensive filtering and sorting is available to make it easier to manage a large collection of files, and access is available to terminal with a graphical interface.
With features such as temporary stacks, built in file editing tools, support for cover flow and much more, Path Finder is an evolution of Finder that is highly flexible while maintaining a familiar look and feel.