I think that it is a relatively new technology that has trickled down from motosports. After a big crash over 3 weeks ago in the WBP that resulted in a concussion and an ambulance ride to the Whistler Clinic, I want my next helmet to have all the safety features that it can. I've been told by shop staff that removable cheek pads are also a big plus.
I think that online from the US is the way I'll have to go.
Was in a similar situation recently, cracked helmet, concussion, luckily not hospitalized but it was pretty serious, and had to spend a couple of months off the MTB, road bike has been OK.
Did some research and the marketing points to MIPS helmets (tech that protects against rotational impact in addition to the regular direct impact) being best with the POC DH w/MIPS as #1, then all other mips helmets and finally the Troy lee D3, Spec. Dissident (both have chin safety ratings) as well as the Bell 9 tied for third. Although, since it's moto tech, maybe MX shops would carry it.
Marketing is really what's available because I couldn't find any German bike mag independent testing :D
Also, lots of guys like the Kali lids and they have some good tech to back up their safety ratings.
I bought the dissident because it fit best. Main line is that a well rated helmet with a very good fit will be best. The worst thing is to have movement inside the helmet while you are crashing. Dissident also has the Eject tech built in, but the shop didn't carry it and I don't know where to buy it either. Also interested in where this thread leads.
"I know that heroes ride bicycles" - Joe Biden