I'm not sure of the per item weight, but when in my full loadout (including rifle) I tipped the scales at 231lbs and my normal weight (clothed w/boots) was about 175. So, even 10lbs of weight savings would be a huge benefit.
loadout would be IOTV w/front/rear/side plates, 8 mags, and misc crap stuffed in various pouches, med kit, Kevlar, M4 w/ pec-15 & ACOG, then small ruck w/ some power bars, 4 extra mags, couple of smoke grenades, laser designator. (prob less then 10lbs)
Dan