Fortunately, they have nutrition info on their website (see link above), so you can find out just how unhealthy they are. And the information is scary!
For instance, their Sierra Turkey sandwich has 950 calories, with 14 grams of saturated fat (that is 74% of my daily allowance for saturated fat), and 2390 mg of sodium (more than my day's allowance of salt).
The Tuscan Chicken sandwich is a bit better at 720 calories, 7 grams of saturated fat, and 1530 mg of sodium.
You vegetarians can have a Portobello & Mozzarella Panini for 750 calories, 14 grams of saturated fat (37 grams of total fat), and 1200 mg of sodium.
Now from that, you are probably picturing big honking sandwiches that any sensible person would only eat half of, but no, that's the charming part. The sandwiches are actually very compact (as in the picture above, from their website). When you get the stuff brought in for lunch, they come wrapped as half sandwiches, but nobody would call the half sandwich a meal by itself. If I could eat only half of the sandwich, it would be a reasonable number of calories, but still unhealthy.
Knowing what I do about their nutrition, I'd certainly never go to their restaurant on purpose. I guess if oily sandwiches were my favorite food ever, it would be OK as an indulgence, like eating at Chuy's, but I'm not that fond of sandwiches, and calories are too precious to waste on mindless eating of things that are way more calorically dense than they seem. (Even at McDonald's, you can get healthier food than this.)
Oh, and for people who are concerned about additives and the natural-ness of food, this ingredient list does not inspire confidence (this is for the mushroom/mozzarella sandwich):
Rosemary onion focaccia [Unbleached flour (wheat flour, malted barley flour), water, potato pieces (potatoes, mono & diglycerides, sodium acid pyrophosphate, citric acid), asiago cheese (pasteurized milk, cheese cultures, salt, enzymes), olive oil, onions, salt, yeast, rosemary], portabella mushrooms (marinated with water, balsamic vinegar, soybean oil, dehydrated garlic, salt, sugar, spices, dextrin, garlic extract, corn oil, red chili pepper, chipotle pepper, natural flavors, natural smoke, xanthan gum and propylene glycol alginate for thickness, potassium sorbate-to protect flavor), carmelized onions (onions, soybean oil, balsamic vinegar, distilled vinegar, water, salt, dehydrated garlic, natural & aritficial flavor, potassium sorbate, caramel color, propylene glycol alginate, spices, xanthan gum, sucralose, calcium disodium EDTA), fresh mozzarella cheese (pasteurized cultured milk, enzymes, salt), basil, salt & pepper.