I live in NYC, and have gone to every Jets/Pats game at the Meadowlands for the last 7 years, except 2 years ago when it was a Monday night game the day after Xmas. Anyways I have always had decent experiance. I usually go with a few Jets fans buddies of mine, as well as a Pats fan friend of mine, and we all have a great time, cheerfull ribbing between us. And for the most part have the best tailgates. Very much like in Foxborough. Its a great tailgate place. The Jets fans are not that bad, you may hear some things yelled at you. But mstly its good natured stuff. As in any stdium you can have a few bad apples, who may throw stuff at you, but that is few and far between.
As far as the stadium the other poster brought up a great point. They are building the new stadium, and a lot f the parking lot cant be used, so they are shuttling in from remote spots. So get their real early to the main lot before its filled, do not park in the remote lots. This is year one of the new construction, and since this is game 1, it wil be pretty chaotic and I am sure annoying.