XENOPHILE  Check out Pref Setter, it's comparable to PlistEdit Pro except that it's free.  
(Version 1.4.1)

XPLICIT  With every copy of Mac OS X comes Apple's Property List Editor (install the developer stuff). I guess, comparing the features of both apps, it does the same, oh, and it's free.  
(Version 1.4.1)

EASER  Does the free Pref Setter do the same thing? I honestly don't know. I use Apple's free program, but I remember coming across Pref Setter awhile back.

http://www.macupdate.com/info.php/id/17002/pref-setter  
(Version 1.3.1)

LEXICON5  Well Property List Editor has not failed me yet and it's FREE. I could see $10.00 but no WAY $24.95. At $24.95 you brush aside those that might need it but find the price too steep. Price it at $10 or $15 and you get more customers. More customers means more money if your product works. As for now, the only comments and reviews people are seeing is "Price Too High" and a paid advertisement by a friend of or the developer.  
(Version 1.3.1)

MARUKO DRINKING TEAM  Look, sure, you don't need this app if you are a Mac developer. But if you are, you don't want to use a text editor. That might be fine if you only need to make a couple of edits. And Apple's plist tool is only very slightly better.

If you are frequently revising plist files used in complex apps, they often contain long lists of default preferences, configuration info, etc., and PlistEdit Pro will save you a lot of time: smart row-based cut and paste, drag and drop, undo, the ability to duplicate large dictionaries and arrays (or any property list data), and intelligent search features that understand keys and values and let you restrict searching to either or both. If you do much Mac development, the time savings and convenience easily justify the inexpensive price.  
(Version 1.2.1)

ANONYMOUS  I don't really see where the niche for this app lies. plist files are just text files. If you're a developer or 'property list power user' you'll probably want to use your regular text editor on them. If you're not a power user, it's unlikely you'll want to pay $25 for a slight improvement on what's freely available from Apple.  
(Version 1.1.1)