It was fun seeing the crew back together again, but really wasn't charmed by it. Maybe I'd get more of a nostalgic kick out of this if I hadn't binged the series in two days, really didn't like the babysitter angle.
That being said, I really think Biggs carried this whole franchise. He's very good at the physical stuff and has a great flustered delivery. LOVED the milf guys callback. And giving more material to Levy ain't too bad either!
Series ranking: 1, 2, Reunion, Wedding. All worth the time to watch them though I'd say.
One final thought: I was once at a gig and before going on I saw a guy look at his phone, laugh, then say "Ha! Stifler!