I've been to just about all the chain tex-mex chains in the area. I really can't think of any that I haven't eaten at. All in all, Moe's is hands down the place to go for a great burrito. Ingredients always taste fresh and their tomatillo salsa is better than many authentic mexican restaurants. Moe's is also a great value insofar that their burritos are about the size of a football, however, they have just introduced a smaller size for those of us that don't need that much.
Pros: Great food, fresh ingredients, friendly staff
Cons: very, very busy at lunch on weekdays, old portion sizes were too big to eat at one sitting (though that's not really a con).