Engineer's Toolbox
I think it's mostly because ET just doesn't get used too often, much less the ore processing of it. It is a new mod to FTB. I think the lack of GUIs is interesting, but it also makes it harder to work with considering how the sheer amount of stuff a single block can do. I have to say though, it seems to be able to do just about everything. I keep meaning to learn it.
On topic (because I always feel obligated), I wonder if a topic like this is the best format for this. Maybe make a new thread for each week or something? It'd be hard to check in on the new developments if it becomes the usual megathreads these forums get.