All

I went with 6D since they’ve been making helmets with this technology for a long time and seem less likely to get it wrong. I think the ods things are recessed so they let the foam parts rotate a bit and have some cushion, but they’ll bottom out against each other before the rubber is in danger of poking through.

Exactly. "Safest" is very subjective. I too wear a TLD SE4 carbon and really like it. I used to wear 6D and I liked it as well.. But there's a lot of great helmets out there now. Big props to 6D. Until they came along helmet technology was still stuck in the 90's. Their design kickstarted the new helmet technology. So now we all benefit. Although I love my SE4, I'm considering going to the new 6D ATR 2. I just feel they're on another level safety wise.

Best helmet question.... Inherently you are going to get a large variety of answers. Everyone is going to recommend or defend their helmet of choice, and they should, most buy what they feel is the best product to keep them safe. A Bell owner will say his is best, Fly owner believes the Formula tech is best, 6D owner believes Omni tech is the best, I personally believe TLD is the best, the list can go on and on. Do some research and buy the product you believe in, there are likely a dozen or more premium helmets that will...

Not qualified to give you an answer but I am sure both are design adequately to protect your lid. 6D uses a omni-directional damper system and Bell uses 3 layers with different impact ratings with rotational slip zone design for the transfer of energy. I don't have experience with 6D but I have been knocked out a few times (grade 1 and 2 concussions) when wearing the Bell Flex and it did what it is designed to do and that does not mean, I was good to go, it means I did not have any brain damage to be concerned...