Some interesting ideas include
"Source code available to modify or create your own rules"
"Jack on the front of cabinet"
"PC embedded operating system"
Some of these would make fair tournaments a challenge. Create your own rules, do not tell anyone about the secret 100M points shot and become the new pinball wizard (using your machine of course).
The jack on the front of cabinet would have been good on ACDC when playing late at night with the wife and kids asleep.