Had a few moments of utter panic when it looked like DTPO2 Beta 5 had lost some files.
I had added a group from my database to the Sorter. I then tried dragging a folder containing several PDF files from the Finder and dropping it on my group in the Sorter. The folder itself appeared as a new sub-group in my database as expected, but the sub-group was empty, the files were gone from finder, and Sorter silently crashed. I.e. the Sorter tab simply disappeared from the desktop, and Activity Monitor showed no DEVONThink Sorter process running. Fortunately, I found the original folder and files intact in the Trash whew.
It looks like dropping files on the Sorter works as expected, but dropping folders is (rather alarmingly) broken.