Just a few of the problems I came across in the short while I experimented with it:

1) Only running it once, I found that 'PCCEngine' had been added to my login/startup items. I didn't knowingly enable any type of automation stuff and found that rather unexpected. I'd like to be asked first before something like that is done. Not only that, but 'PCCEngine' is a 1.3 MB application that's stored in my Preferences folder?! I'm sorry, no application has any right to be there. If it's a daemon, put it inside the main application's bundle so I don't have to see it or even worry about it. Or, use the Application Support folder like it's meant to be used.

2) The help tags for the "Light Cleaning" option showed that "/Library/Caches/com.apple.LaunchServices.LocalCache.csstore" and
"/Users/~/Library/Caches/com.apple.LaunchServices.UserCache.csstore" would be purged. I'm running OS X 10.3.4, Panther. I would expect that an application with "Panther" in its name would be updated enough to run in Panther. The fact is, those 2 Launch Services files are used in Jaguar, not Panther. Panther uses a single Launch Services file stored at the Local Domain level (/Library/ folder).

3) I saw it had the ability to execute the 'lsregister' command to rebuild the Launch Services database. The menu command is "Maintenance > Rebuild LS Database..." Notice the ellipses. Being a little wary of the app at this point, I hesitated before choosing it. But then I thought "Okay, I should be safe, it should bring up a dialog where I can confirm whether to run it or not--after all, that's what the ellipses signify." Well, I was wrong. It actually executed it immediately. Then it informed me that the Finder needed to be restarted (the Finder should've been quit during the whole thing if you ask me). Having no other option, I chose okay. Obviously, the application used a kill command to kill the Finder rather than simply asking the Finder to quit itself (via an Apple Event). Thanks to that, I lost my Finder window arrangement when I didn't have to. A simple one line AppleScript, "tell app "Finder" to quit" can be used to quit the Finder without losing all those preferences.

I'm sure I would encounter plenty more, but I don't think I'll be using the app much longer....