I kinda like it, especially how it could stabilize the head/neck area. When I went through the MSF instructor program way back in the late 90's, we had to watch a lot of crash video. I saw how violent the head whipping could be.

i picked up my Troy Lee Design jacket today. it has a external integrated back protector along with others.

http://catalog.troyleedesigns.com/catalog/product_info.php?products_id=2160&osCsid=h4aik3bh4u87urhvornchm2b45