As far as I know the show to beat now is the SoCal Arcade Expo.

http://arstechnica.com/gaming/2015/01/a-virtual-day-with-750-pinball-and-arcade-games-no-quarters-needed/

Over 500 pins. They weren't all up and running for the inaugural show, but we still were able to beat the Texas world record for most machines being played at the same time at 330. And as techs have more time with the pins the number fully functional will keep going up.

Arcade Expo, photo by Steve Tsubota

Yeah Friday count wasn't so hot. They had a lot more working by Saturday. Hopeful for the future of the show!

Chicago Expo isn't about the most machines, the free play area is cool, but it's really about the vendor hall and the seminars. That's where you go to see all the prototypes and new stuff, and hear industry people etc. I wouldn't bother to compare it to the other shows that are more game focused.

I hardly spend any time in the free play area at Expo myself.

Assume he means the speaking seminars.

Chicago Expo is all about the manufacturer hall. If you went and were disappointed after seeing all the prototypes and custom games, then, well, you're not excited by the same stuff I am.

The free play halls were nice! But I hardly touched them.

I have no idea what John Weeks still has in storage, but Arcade Expo had around 500 pins.