Joined: Aug 2008
Posts: 13,127
Likes: 2,154
From: Ann Arbor, MI
Bikes: 15 Kinesis Racelight 4S, 76 Motebecane Gran Jubilée, 17 Dedacciai Gladiatore2, 12 Breezer Venturi, 09 Dahon Mariner, 12 Mercier Nano, 95 DeKerf Team SL, 19 Tern Rally, 21 Breezer Doppler Cafe+, 19 T-Lab X3, 91 Serotta CII, 23 3T Strada
They're heavy, poorly vented, and get too warm (which exacerbates the fogging problem due to poor venting).
i can't really think of a good reason to buy one over a cycling specific helmet, or even a board/ski helmet.