What are the pros of using Path Finder, and not Finder?
Could I not get some of the features of Path Finder by adding Applescript scripts to the stock Finder?
Many of the changes in Path Finder cannot be replicated by Applescript scripts because the interface has been fundamentally enhanced. Things like the drop stack, window tabs, dual-pane browsing, integrated terminal, and so forth, cannot just be tacked onto the Finder.
This review should help you discover what Path Finder has to offer: http://www.macworld.com/reviews/product/413028/review/path_finder_502.html