restricted products are only available in some stores, they usually have a different colour scheme and maybe some additional features, e.g upgraded ankle or toe strap on some models.
Reflex is burton's technology for non-EST boards that allows the binding to flex left and right. It's like their hinge tech that is on some of their EST bindings.
If you have a channel board you should buy and EST binding, that is the binding that is supposed to go with the board.
That is not not 100% true the Living Hinge is build into the disk along with removing material from the binding base giving you the reFlex binding. I think you are thinking of the Living Hinge for the hi-back that Burton uses on both EST and reFlex. The EST having the attaching points on the outside of the bindings means they have no base material and you can have more feel and lack of a better word collapse of the binding when you push down that reFlex also has just not as much. Now Burton released THE HINGE in some of its line this year or last year cant remember, that allows you to flex left and right or roll of your foot for better ollies. Hope this helps or maybe I totally lost everyone on this.