collars only protect agains whiplash type injuries, where a brace protects againts crushing of the neck also. Any pressure is passed throught the helmet, into the collar and then onto your collar bones. There is an arguement against as they can break collar bones, but i know which one id rather break.
I ride with a Leatt also. Neck braces are a helmet for your neck.
I notice I'm hotter while wearing the Leatt but it is totally worth it. Not that big of deal when riding but it gets cumbersome at other times. The trade-offs are totally worth it IMO.
I was looking closely at the a stars, sb I think it was? I usually ride every wk end but not racing so I don't feel the need to push hard everywhere I go, so with this I never felt the need for a neck brace and as said use a colar. I am in the middle of "armouring" up the berg and thought mabe I should protect myself a little too cheers for the help!