My longtime Seyberts account rep, who is a very good player as well as a certified instructor, sells all the various makes of balls. His opinion/expertise in the pool cues and accessories industry is valued as highly as anyone I know of. When I asked him his opinion as to which balls are the best, he didn't hesitate in saying the Belgium made Saluc balls (Aramiths and Centennials) are far superior to anything the Asian market has yet to come out with - specifically the Cyclop balls.
We've also heard more than one touring pro player who posts on this site who says the pro players dislike having to play with the Cyclop balls in the tournaments they sponsor. Obviously it's bad enough to the point that I've noticed even some tournaments that Cyclop sponsors, they use an Aramith Pro Cup Cue ball, I'm assuming because the players have complained so much about the Cyclop cue ball.
There is very little difference in playability but the cue ball is another story. I hate the Cyclops cue ball, older and new both suck.
Aramith cue balls are my choice.