According to this the difference in X ring to O ring is the shape of the seals, and the X seal is supposed to keep dirt out better, but as I read the "better" job it does is not justified to it's cost against the O ring chains. And reading on the PJ1 blue label vs. black label.
black labels literature:
Heavy duty, thin-bodied lubricant penetrates chain rollers. Molybdenum disulfide and synthetic sperm oil added. For standard and o-ring off-road chain.
blue labels literature:
Gives o-ring chains longer life
Keeps o-rings moist and pliable
No messy fly-off
Sounds mostly like the black label is for off road and any O ring or standard chain, and that blue label is for basically motorcycle O rings. The magazine that I read said the black label had the least amount of fling off, I think either can be used, but since I've been using black label for, who knows...ever? I'll try the blue label to see if I notice a difference, which is in about 15 more miles but a half a can of black label left, when I do try the blue label and if a difference is noticed, I'll find this thread and post. :drink
In what way is chain wax far more superior, I'm interested in finding something new, I'm satisfied but always interested in better products. It sounds like the label is saying just what the black label says. For standard and O ring applications.