When it works properly, InvisibleFile does exactly what it should. It makes whatever file(s)/folder(s) you specify completely invisible and impossible to find. When it's not working properly, the files you make invisible become corrupted and cannot be opened (or even made visible). This has randomly happened to me twice. DO NOT USE THIS APP IF YOU ARE NOT USING TIME MACHINE TO BACK UP YOUR FILES!!! Everything I've lost due to this app's glitchiness has been saved soley because I was able to restore my files using Time Machine. Otherwise, they'd be gone forever and I'd be giving this app 1 star. In testing, I've come to the conclusion that InvisibleFile won't corrupt the files you're trying to hide as long as you keep those files/folders located on the desktop. DO NOT HIDE FOLDERS WITHIN FOLDERS. Keep ONE folder on your desktop containing NO OTHER FOLDERS and only the files you want to make invisible. Make that folder on your desktop invisible and you should be safe.
Now, this review was written pre-OS X Lion. BEWARE: CURRENTLY, THIS APP WILL NOT OPEN IF OS X LION IS INSTALLED ONTO YOUR MAC. Until InvisibleFile is updated to run on OS X Lion, it is completely useless.