Based on what I've seen on tape, neither the Bengals nor the Steelers is having a particularly good year on offense. For different reasons, these teams are just not as consistent when they have the ball as they were last year.
In 2009, the Bengals had an identity. They ran a lot of heavy formations, with two tight ends and the like, and they pounded opponents with their running game. They were physical first. They did take advantage of one-on-one wide receiver matchups on the outside, but they were definitely a run-first team.
This year, they've become pass-happy. They are spreading out their receivers, but it's not working. The offensive line just can't get the job done consistently. Not to pick on one guy, but tackle Andre Smith, for example, is very vulnerable to an inside speed rush. The stats say he weighs 345, but he looks and moves like he's carrying a bit more. It's possible a pass-first approach could work against the Steelers, because running the ball against Pittsburgh is tough. The Steelers' run defense is the best in the league. It gives up 58.9 yards per game, nearly 25 yards better than the next-best team.
For the Steelers' offense, throw out the first four games they played without QB Ben Roethlisberger. He is their linchpin, maybe now more than ever. They have not established an effective running game, and their receivers are average. Hines Ward is a solid receiver but not much more. Mike Wallace is not a very polished pass-catcher. And Antwaan Randle El is really just a get-open sort of guy. None of them scares a defense. This offense almost always comes down to Roethlisberger making plays at crunch time.
I think the key to the game will be first down when the Steelers are on offense. They have struggled all year against sub-packages designed for obvious passing downs. Cincinnati CBs Johnathan Joseph and Leon Hall are very good corners who can cover well and stuff the run a bit. So if the Bengals can put the Steelers in several second-and-9 or third-and-7 situations, the game could come down to how many plays Roethlisberger can make when everyone in the building knows he's throwing it.