Rated 4 out of 5 stars

This is a really nice idea, but I had issues with the chronological order of emails after customizing the "year" format. I wanted to use the add-on to shorten the standard date format to save horizontal space. So I reduced the "year" format from the usual 4 digits to the last two digits (like 2012 to just 12). It works, but then the chronological order of emails gets mixed up (especially if new mail arrives). One can correct the mixed up order, shortly, by clicking on SDF's own new "Date" column again, but it keeps reverting to the mixed up order. Had to deactivate the add-on. It would be nice, if the add-on could keep the logical chronological order of the standard date format while displaying the new customized date format.

This review is for a previous version of the add-on (1.0). 

Thanks for your detailed review! All of this has been fixed in version 1.1.