My low rating is based only on safety. Sandwiches are incredibly good; I really recommend this place if you're not as sensitive as I. But a few weeks ago, a poorly trained and enthusiastic cashier assured me I'd be safe and I wasn't.
The chain owner took the time to reply personally to my complaint; he seems to take health very seriously and says his staff are rigorously trained to be as safe as possible but to not promise that cross-contam is unlikely.
I wish they could train staff to prep even more safely. I'd eat here all the time if I could. Again, I highly recommend for those who don't have to worry about trace gluten.