Miami is a far better defensive team than the Cavs, and Pat Riley is a better defensive coach than Mike Brown. Cleveland is really a very mediocre defensive team.

The Heat have holes on the perimeter, and their screen/roll defense is atrocious, though. Jason Williams, Antoine Walker, and Shaquille O'Neal are terrible defenders, and the ability of Gary Payton, Dwyane Wade, and Derek Anderson to contain on the perimeter is inconsistent.

And keep in mind that Cleveland's best defensive player is Ira Newble, who couldn't get off the bench. It's unclear how much Shandon Anderson will be playing, but Riley has no qualms about using James Posey.

And Miami has Alonzo Mourning.

Two minor additional objections: The Cavs are not a young team, and the young players they do have (James in particular) are generally among their worst defenders; and New Jersey was a fantastic defensive team this season, #3 in points allowed per possession.