3.5-4. Whew; this is a really ambitious little ode to art that evokes a lot about the state of what it means to be an artist and a critic. Like a good chef, it doesn't seem to waste any of its ingredients, near as I can tell. Though the humor didn't always land with me, it's never really offensive; and if it doesn't elicit laughs, it goes down pretty smoothly with the rest of this warmly realized allegory.
Has all the narrative balance and nuance as the European neorealist fantasies that it tips its hat towards (Miracle in Milan comes directly to mind). And just like those, it is sweet and warm but there's a degree of harshness, a kind of melancholy bitterness that improves with (audience) age. A combination of diverse flavors lends it an intense complexity that rises above imitators. Of course this is a food metaphor.
It's hard to like rats... unless they're made by Pixar in outrageously beautiful animation. To paraphrase the movie's most famous line, not every story is great but great stories can come from everywhere, and that hasn't been more evident since Pixar's debut. They've been pushing the boundaries on animation and narrative alike creating the most inventive stories in cinema. "Ratatouille" is just one of them.