Chipotle is set up like the burrito version of a Subway. You order the basic item, and then walk down a row of possible toppings that the employee can put on your burrito. Because you select the individual ingredients, it is very easy to make a vegan or vegetarian meal.
I rated them three stars only because the majority of times I've been in, the employee's been so quick which the cheese and sour cream options that I almost didn't decline fast or loud enough to avoid ruin.
Portion size is huge at Chipotle. Expect leftovers.