Hmmm.
Given that fleece is cheap, light, insulates and can be made wind-proof..and down is light, packs well and has great insulation properties --the aero-vest would have to beat either of these materials.
So...
Some light, non-disposable alternatives linked below*
a 9 oz fleece vest at a great price 6 and 7 oz down vests another light vest -- spendy! a 14 oz fleece vest for under $20 * nope. Not affiliated with any of these co.'s