Hilarious. And has aged a lot better than most of Harold Ramis' and Chevy Chase's films. Still really edgy and charming after so long. The film really ushered in the modern family comedy of "Married... With Children", "Simpsons", "Modern Family".
Definitely better than Caddyshack, and the flip out scene demonstrates why: "We're all gonna have so much fucking fun we're gonna need plastic surgery to remove our goddamn smiles! You'll be whistling 'Zip-A-Dee Doo-Dah' out of your assholes! I must be crazy! I'm on a pilgrimage to see a moose. Praise Marty Moose! Holy Shit!"