I created a macupdate account just so I could comment on this app. It is great! There are a lot of EXIF data "viewing" apps. But few to EDIT the EXIF data.
This that do exist require the command line. Reaveal is not a command line tool. It has a GUI.
Simply changing the creation date with File Buddy or another app DOES NOT change the EXIF data. The "photo taken date" remains the same (in the EXIF).
I have Kodak cameras and this allows me to change the date and other info when I forget to reset the date after charging the battery.
One flaw is the inability to do several photos at once.