Unless I've missed something over the last 25 years of playing pool, chalk is the substance that helps increase the friction between the cue tip and the cue ball, thereby allowing you to make the cue ball move to the next desired location. Right?
As we all know, miscues happen for two reasons: (1) a really bad stroke (i.e. dropping your shoulder or jumping up), and (2) not enough chalk on the tip to adequately grip the cue ball. (If I'm missing a 3rd reason, please let me know.)
Once you've played pool long enough, you understand the incredible importance of chalking your cue tip before every shot. Therefore, nearly all miscues are due to a bad stroke. My question: Is more expensive chalk going to fix a bad stroke?
As far as the actual differences between chalk brands, who knows? Each company has their proprietary blends of chemicals. The real question regarding the differences in chalk: Is there a significant difference in performance from brand to brand that justifies the very significant differences in price?
For instance, I'm sure every player has used Master chalk at one point in their pool playing career. As far as I'm concerned, Master works just fine. As a matter of fact, it works perfectly. And the price is incredibly reasonable, ranging from free on the rail of the table to $0.25 per cube (and that's full retail).
Now, let's examine all other chalks more expensive than Master, such as Blue Diamond, Kamui, and the new Predator chalk. Do these chalks offer a SIGNIFICANT improvement over Master to justify their lofty prices. By the way, if you don't think that $2 for chalk isn't expensive, you're fooling yourself. Yes, in the grand scheme of things, 2 bucks ain't that big of a deal. But, in general, $2 for a 1 inch cube of chalk is quite ridiculous. And don't even get me started on a $30 cube of Kamui!
Anyway, back to whether or not expensive chalk offers a SIGNIFICANT improvement over Master, I'll just say this: If those expensive chalks offered ANYTHING that Masters chalk cannot provide, every single pro pool player, snooker player, and billiard player would use them. EVERY. SINGLE. PRO. The fact that ANY pro still uses Master proves the other chalks are just hype.
And don't give me that foolish argument that you only have to chalk your tip once every three games with brand X chalk. My response to that is: whatever. If you're playing a big set or the finals of a tournament, are you really going to chalk your tip once every couple games? No, you're going to chalk every shot.