I've been thinking about comparables for the defenses in Montreal and Hamilton, and find myself coming back to Bob McGowan's evaluation of those classic Pittsburgh Steelers / Baltimore Ravens matchups from a few years ago. What he said roughly was: when you watch Baltimore's defense, you get this feeling that they are flat-out scary, that they will do whatever they want to you and there is nothing you can do to stop them. Whereas with the Steelers, they're not terrifying, but at the end of the game, you look up and you just don't have enough points on the board.
It seems to me that McGowan's analogy works pretty well to describe the Als and Cats. Essentially, our D is the Steelers (complete with Chip Cox as the Troy Polamalu-rover type playmaker), while Hamilton's D is the Ravens.