Of all the Francos right now, Dave Franco is the Daviest.
In other words, it's silly to compare James Franco and Dave Franco because the more we see of the two of them, the more it becomes apparent that shared DNA aside, these guys are radically different performers.
In "Neighbors," Franco plays Pete, the right-hand-man to Teddy (Zac Efron). The two of them rule the frat in the film and exist as a sort of living embodiment of the bro code. One of the things that "Neighbors" does well is the way it begins with broad stereotypes and then reveals the characters to be far weirder than they originally seem. Franco's character emerges as the "smartest" of the frat guys, an admittedly low bar, and his relationship with Teddy drives the film is some very funny directions.
Franco also returns in "22 Jump Street" this summer for at least one sequence, teased in the red-band trailer, and that's good news. His role in "21 Jump Street" was a breakthrough for him, and part of what makes Franco such an interesting comedy presence is because he looks like Hollywood's typical idea of a leading man, but he's a stealth weirdo. The comedy choices he makes are deeply deranged, and watching him and Zac Efron work together in "Neighbors," they both seem more than happy to burn down any expectations people have about them based on appearance.
I suspect that part of the reason Chris Mintz-Plasse took a relatively small role in "Neighbors" was so he could hang out on set with Franco for a few months shooting what is basically a perpetual party. The two have worked together a few times now, like in "Fright Night," and Franco made it clear that if he had his way, he'd just spend his whole career making movies with his friends.
If they all end up as strong as "Neighbors," I would be fine with that.
"Neighbors" is in theaters this Friday.