Not that it makes that much difference, but if you are the Heat, which team do you prefer in the next round? If the Nets win Game Seven, they go in with a bit of momentum having to come back from a 3-1 hole. If the Bulls win, you get the possibility Derrick Rose could decide to play, plus they have more playoff experience.
The Nets clearly have the better center in Brook Lopez, which seems to be the only thing that gives the Heat any trouble. With Noah hobbling, Lopez presents more problems.
Neither team should give the Heat much resistance, but in the early rounds it is nice to get as little as possible. You'd like to be as fresh as possible by the time the Finals start, so the fewer games against the East the better.
If I were the coach of some mythical team and you asked me which team I would rather play between Brooklyn and Chicago, I think I'd take the Nets. Chicago seems to be the tougher of the two against the really good teams. They snapped Miami and New York's long win streaks late in the season.
Of course, no team should worry the Heat as their second straight title is a mere formality at this point. The only thing that could derail it would be (knocking on wood) an injury to Lebron James. With that in mind, I think the Bulls would be the team more likely to inflict an injury. Not that the Nets are soft, but the Bulls are just a physical team.