Several issues here...

I was hoping I could use this app to do just one thing: change the timestamp on the JPEG file to match the date and time found in the EXIF header. But alas, it couldn't do it. :( The preferences item to set the "File Date and Time" affects only the EXIF field, "File Date and Time," *not* the actual file's timestamp. Better documentation would eliminate confusion on this topic.

Even if updating the "File Date and Time" tag was what I wanted, there's no easy way to do the modification. The app won't do anything to the file unless you tell it to modify either the file name or EXIF "Image Date and Time." I don't want to change either one! If I nudge the time up by 1 second, then it works.

The user should be able to do batch transformations by just dragging a folder onto the app's icon, versus launching the app, selecting File -> Batch Change...

The Batch Change control pane promises some nice features, but a glaring omission is the ability to check/uncheck all by clicking on the column header or something. If I open a folder with 100 images in it, and don't want to touch their filenames, I'd like to have an easy way to unselect the "Change File Name" box for each image. The fact that it shows you the changes it's about to make helps out here, but it would be nice to just know that things won't be updated unless you want them to be.

Great concept though! I'll update my review if these issues are resolved.