I'm a heavy ACAD user and I'm just discovering how easy SU is to use but I'm having trouble with some options that just aren't there....Does anyone know anything that would help me perform the same ACAD commands?

-Fillet
-Middle of two points (object snap)
-Mirror

Is there anyway to manipulate the UCS....Sometimes I feel like I'm aimlessly trying to snap to the correct axis....
I've also heard that there are Ruby Scripts to help convert ACAD drawings like 'Close open lines' but I can't find that script anywhere.

any help would be greatly appreciated....