I agree with KEN. I've had an INSPASS (PORTPASS) since they were first being issued. No one checks if you make 3 or more international business trips a year and the machine doesn't care if you are on business or pleasure. The biggest gripe I have is that the kiosk almost never worked when I was coming thru customs. True, you can go to the head of the adjacent line at that point. However, in my expereince, returning through EWR many times, US residents clear very quickly. Its different if you have a foreign passport. You can get stuck in a line behind someone entering from an obscure country and the wait can be considerable. For foreigners, INSPASS is a blessing. In fact, when I go annually to renew mine (Its due now), I tend to find mostly UK residents there renewing theirs.
IMHO, the best part of the INSPASS is that its cool. I get lots of stares when I use it to check in for flights and use it instead of a driver's licence for a govt issued ID document. I just tell the agents its an "electornic passport" (which it isn't) and they just nod and hand it back.