About those units, I would laugh if I herd anyone say "mebibyte"

My usage is not limited by the way yours is at all. I can use as much bandwidth in a month as I want, no 10GB limits. As for my transfer speeds, I am not exactly sure whether there is a cap or not. I do know that in my area the total bandwidth of everyone on an individual node is shared, but I think it is shared dynamically. I get as much bandwidth as I need provided that no one else is using it. The good thing is that in my area even on peak hours I still can not detect a noticable drop in speed.