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