I know there is a formal thread elsewhere - but as that has to be moderated, it's not ideal for quick thoughts. 

I'm testing it out & in general liking it, though I can see a few potential glitches for the way some of our staff work. 

We use anonymous marking by default, and some classes are big, so they use groups from within Blackboard to identify marking groups. 
The old filter at the top was useful to allow staff to pick up just their students (even when anonymous). It was never perfect, as you had to return to the inbox to get to the next student on your list  - the next paper navigation in FBS took you to the next in the unfiltered list. 
However, I can't see a way to do that in the new one, without reverting to a system we used a long time ago (e.g. 17 submission points, adaptive release in the course to allow the right students to see the right submission point, and then a calculated grading column to collate all 17 sets of marks into a single set)

I think (some) staff will also miss the analytics tab, in particular the no of students who resubmitted, the average time between grade release & students actually looking ... The admin view of the stats isn't as clear as those at assessment level.