I dive every day I log in, usually after I have collected all of my DC rewards and before I check on my Aquarium. Even though I do receive items worth next to nothing most of the time, I tend to receive a few gems now and again. My first big item I received from DD was Purple Tam Beret which I sold for over 200k. I also received a Thank You Letter for August 2006 and sold that, and back at the beginning of December I received an Ascended Demon on a mule that I now have in my inventory. As for this event, I have yet to receive anything of value.
I DD every once and a while. And while I've heard all these stories about people getting pretty decent items, I myself have only really gotten paper. xd Doesn't really bother me though. I don't really expect getting anything extravagant anyway.
As for personally donating items.. Like many I only did it during the event. So many crap items and zOMG recipes. And even after that I still have tons of unwanted zOMG recipes left.. @_@
I sort of wonder who's getting all that junk I threw out... xd