Of course a neurosurgeon is gonna tell you to not wear a helmet, he needs you to help buy his yacht. I don't care what all those wordy scientists say. I'd rather have an inch of good styrofoam protect my head in a fall than try to be scientific and see how my head fares when it hits bare concrete unprotected.
I'm very happy with my Limar 550. It keeps me cool and the price is right. A good cheap Bell Helmet is a great way to go too.
Ernest