I had never heard of Freebirds before this thread, but was in the Dallas area last week and one happened to be right across the street from my hotel. They seemed to have more variety of salsas and sauces, although they don't offer brown rice. It's also handy that they offer their burritos and bowls in three different sizes vs. just one for Chipotle.

I liked Freebirds a little better than Chipotle, my wife gave the nod to Chipotle. I could see where the comparison could easily change depending on the options chosen and how you dress it up, we've had years to fine tune our Chipotle orders.