Took me 3.5 hours on easy, around 5-6 on regular. Just shows the difference between the two, no wonder you got bored.
But it's still a hell of a lot better in the BFBC2 campaign than in MW2. MW2 is like an arcade.. you're a 1 man army that's getting shot at from every angle possible. In BFBC2 you actually gotta work with a team.