CAX will feature a big chunk of the combined collection of Mark Birching and TJ Beyer. TJ is the top bay area pinball operator, and their collection includes an original Big Bang Bar and Kingpin. Both of them are principle show organizers and pinball enthusiasts. This is definitely a show for players.
As for buy/sell and vendors, PAGG is probably the better show. CAX is a celebration of the old school arcade. I've gone the last five years and I can tell you, there is no better!