It's fascinating that there are so many opinions on cue balls that are, with exceptions for the Cyclops ball and the imitations of first quality cue balls, made by the same manufacturer. Aramith manufacturers virtually all of the balls discussed--including the Centennial, of the same materials, to the same specs, and to the same quality standards. I contacted Aramith a few years ago and confirmed that all of the top flight balls that they manufacture are at least intended to be identical*, the only variation being color markings or the spots on the measles ball. My guess is and has been that quality control variations between balls and psychological variations between users combined with a comparatively small sampling gives the impression of some consistent variables in the balls. Or Aramith deviated from the truth. Somebody might want to ask them again.
*Cue balls made specifically for bar tables are also an exception.
John B.