I bought one of these by chance, as I felt that with commuting in and out of Leeds, i was risking the unthinkable. As an experienced rider (15+ years competitive level of Cross Country racing) I thought I'd always be able to avoid a compromising situation on the road, yesterday however I was proved wrong when a car came out of nowhere and smashed into me, sending me over the bonnet, causing me to land on my head and shoulder on solid tarmac. Luckily my neck wasn't broken and my head was protected by this helmet which now has two large cracks through the top of it, which would have been my skull. The Police said I would have almost certainly died without the helmet.
It may not look so cool to wear one, but jazz it up with some sunnies, swallow your pride and wear one.
Lastly, I'd say make sure you tighten the straps suffciently sufficiently to ensure the helmet covers your head if you pull it from side to side, front and back.
Hope this helps someone.