800 Power-fill down = 1.68 clo/oz Dry and well cared for, wet not so much
Primaloft one = .92 clo/oz Dry and .9 clo/oz wet.
Climasheild XP = .82 clo/oz
So down per oz is king, but if your going to get wet, like Ryvr said. You cant beat a good synthetic.
clo/oz isn't everything, construction as Warbonnet guy pointed out makes a difference too!