Greg Ritter did a session on this which I went to. Having spent the last year studiously avoiding TII, I did fid that I didn't know what questions to ask, but this is what I did find out:
Assignments will be more or less identical to ordinary BB assignments, and you will be able to access reports via the gb.
Work will be submitted to the institution db, and optionally to the Global db.
Draft submissions are possible, but it wasn't clear whether you could do draft only.
Staff can submit work directly without going via an assignment.
Reports take minutes rather than hours to generate.
Reports use lots of AJAXy stuff to make them easier to use.