Bulls are 6-2, have numerous wins against quality opponents.
Were the wins all against quality opponents?
not all, no . . . but they have more wins against quality opponents than the Celtics (the C's have none).
Bulls have beaten the Hawks, Lakers, Magic, Clippers, and Grizzlies.
Make that the 7-2 Bulls, who are scoring about the same as the C's--but holding opponents to 8 fewer points.
Yeah, what the Bulls have going for them is that they're a truly elite defensive team (the C's aren't anymore -- just a pretty decent defensive squad), and they have an elite 1-on-1 scorer, plus a couple solid complementary scorers, one on the wing and one in the post.
Their offense overall is just about average, but late in a close game they have somebody they can rely on to make tough shots against any defense. They also tend to have significant leads late because of their elite defense, so they're in close games less often.
The C's don't have a player they can lean on for buckets late in a tight game -- and they tend to be in tight games late much more often.