Charles,
I've got a number of CBFs and can't say I've ever attributed them with increased brightness. I've also not tried any of Alan's newer CBFs... I quit buying after the Signature and Infinity versions. Which do you have?
What I like about the CBFs is that there is no breakin time and, generally speaking, they convey a quieter, more relaxed presentation. I tend to think there is a point of diminishing returns but that likely depends upon where you put them.
I will say that despite the quality of my system, and the number of Alan Maher or other power conditioning accessories in my system, or any number of other tweaks, I still have days where the sound of my system is worse than it was the day or two before. Whether that is due to power issues, or my state of mind, or the health of my ears is anyone's guess.