Email in DT Pro versus Pro Office ?

I’m starting to use DT much more for email storage. At the moment I only have DT Pro, not DT Pro Office, and was wondering what extra email features the Office version brings? The online help hints at it, but I can’t find any details on the web site or elsewhere. Can someone point me at information so I can decide if it’s worthwhile upgrading?

Also, if I upgrade, what happens to the existing emails i’ve imported (mostly via drag+drop) … do I have to start over?

Thanks!
–Tim

P.S. I use both Apple Mail and Entourage.

DEVONtech, quite thoughtfully, provides a lengthy feature comparison on their site with the details you want.