They're both pretty funny. I found Role Models the better though. Zack and Miri was a straight out comedy, with a weaker storyline. Role Models I thought was pretty built up and hilarious. Oh if you haven't watched the movie Sex Drive, I'd recommend it if you liked these movies. It's classic amazing, especially the unrated edition on the DVD. It's 20+ minutes longer and they stuff it with bloopers and random things.