My own preference now is a Mini clamped on each flash stand. Makes it easier to move as a unit, no power cord off one unit to another strobe to trip over, and I can leave one off if I am only using one strobe and the other as a backup or fill strobe as needed.
If I only could own one pack to two heads, then the Extreme and dealing with a 25 foot power cord to the remote head. But I really prefer two separate systems, hence the Mini, on their own stands with a much shorter coiled power cord like the one in the link below.
http://www.allelectronics.com/make-a-store/item/lcac-427/3-iec-coil-cord/1.htmlMack