I'm obviously preaching to the converted here but I'd feel very strange flying around without a bone dome.
I've banged my head countless times whilst attempting resus, the dark visor is more practical (and less wannabe) than a pair of Oakleys and the clear visor invaluable during hot loads.
My only 'helmet pet hate' is fellow crew members (a minority) who insist on wearing one away from the aircraft during an incident. They cannot hear a thing and risk damaging a valuable piece of kit. We provide kevlar safety helmets for that sort of thing!!!
Also, most UKHEMS operators require paramedics to share helmets (normally 3 between 30) often resulting in an ill fit (despite multi-fit velcro tabs). I know it's probably a charity/money thing but surely a lose helmet is going to do more damage than good if we cream in?