In order, I prefer the Kamui (either one, I can't tell a huge deal of difference), Predator, Blue Diamond and then whatever. I believe the consistency of the grit size for the Kamui is better than any other chalk. I like how easily it goes on the tip. It will go on the tip and stay when other chalks won't. So you don't have to dress your tip as often. I like how it stays on. In particular, I really like how it easily coats the break tip (ceramic or hard leather). Even though I lightly chalk for prior to most shots, I like how it lasts for a long time if you don't want to, forget or whatever. I don't chalk as much when I'm practicing. I also think, since the Kamui goes on with such a light touch, it will extend the tip life. Chalk is an abrasive. So if you're rubbing chalk on with more strokes and/or more pressure, you're slowly wearing your tip down.
The downside of the Kamui, as most say, is the marks it leaves on the CB. I just make sure to wipe the CB between racks. I don't see price as an issue as it last at least 3 to 6 months depending on use. The math says it costs a quarter or less per day.
Assuming you get an even, complete coat of chalk, I don't believe any chalk makes any difference in "gripping" the CB. The uniform grit might make a miniscule difference but I can't imagine that would be perceptible or make any difference to the vast majority of players.
What would I look for in evaluating a chalk choice? Goes on easy with few strokes and light pressure, provides an even, smooth coat of the tip and lasts longer - in that order of priority. If you could achieve that near what Kamui does, diminish the CB marking, I'd replace Kamui with that chalk. Obviously, it would be nice if the price were lower but again, looking at the cost on a per day usage basis, I don't find the price of the Kamui to be a factor in my decision.