With all of these comments in favor of them I will add one criticism: I tried one here in the frequently cold and humid Pacific Northwest and found that I couldn't avoid fogging my glasses* while wearing it under a helmet. This was the style with only a small opening for one's eyes. Therefore, should some sort of neck cover ever become required, I'll be looking into either the style with a large opening for the entire face or one of those helmet skirt things.
*Yes, they're prescription lenses. No, I can't see well enough to drive without them. No, I have no interest in contact lenses.
1982 MG Metro 1300: IOE 2015 Pacific Northworst GP, Longest Distance 2010 Cd'L Box Wine Country Classic
1980 KV Mini 1: Worst of Show and Fright Pig Supremo 2009 Concours d'LeMons
1978 H Special: Second-Round Elimination 2010 LeMons Pinewood Derby at Sears Pointless
1967 SAAB 96: IOE 2012 Pacific Northworst GP