I've only been once and can't comment on the other sandwiches, but the Cour d'Alene hot sandwich is awful.
The "roast beef" is essentially dog food: it's shredded and bathed in a strange tasting sauce that my white bread wouldn't absorb. Unfortunately, the sauce is necessary: the meat crumbles and falls everywhere without the goop holding it together. Regrettably, it tastes like it looks.
Otherwise, the white bread was good: buttery, but not too rich, and the au ju had a nice flavor, but the shredded meat paste was just too much.
I won't say don't go to Silver Mine at all. The cold subs look promising, but skip the Cour d'Alene at all costs.
(If you are really in the mood for a processed meat product, head over to State Street Brats and pick up the chicken wings.)