But if you study James' and Nowitzki's career arcs, you'll find incredible similarities. Both were teenage prodigies. Both are in a select group of NBA players who are unguardable. Both, whether fair or not, have had to shed the perception that they couldn't close games. Both also have lost in the NBA Finals.
But the bigger tie that binds LeBron and Dirk together is what's at stake for them in this series.
No one else in the Finals has more pressure to win than LeBron and Dirk because they are two of seven NBA MVPs who haven't won a league championship.
"I'm not really worried about it," Nowitzki said. "That label is not anything I'm worried about. I worried about winning. I'm not worried about my legacy at all. I'm worried about being on the winning team. It's about ending the season with a win."
Pity the loser of this series because not only will he remain a member of that distinctive class but also, it's safe to say, he could put his legacy on a different course.
To be fair, LeBron and Dirk both deserve a huge amount of credit for how they've grown since losing previously in the NBA Finals.
In 2007, LeBron had some of his worst postseason games against San Antonio, which swept the Cavaliers in what was a lopsided, dreadful NBA Finals.
Contrast that with 2011. LeBron, despite all he has accomplished, seems to have had a coming-out party in these playoffs and has shown a level of comfort and patience late in games that he didn't always display as a Cavalier.
"I go back and look at some of those games, and I'm a better player than I was," James said. "That comes from playing in those types of games. Winning, losing and just trying to become better. You just use it as fuel."
Likewise, Dirk has come a long way since 2006, when the Mavericks failed to close out the Heat after establishing a 2-0 series lead.
Nowitzki was fantastic in the Western Conference finals, averaging 32 points per game against Oklahoma City. And even though Dallas lost Game 1 to the Heat on Tuesday, Dirk's aggressiveness in driving to the basket didn't waver. He scored 27 points on a night his teammates had an uncharacteristically bad offensive performance.
LeBron's free agency was arguably the biggest story of last year, but let's not forget that Nowitzki also could have chosen to leave Dallas this past summer.
Joining Dwyane Wade and Chris Bosh in Miami certainly put a lot of pressure on James to win immediately, but Dirk wasn't exempt from expectations just because he chose to stay with the team that acquired him in a draft-day trade 13 years ago.
Like LeBron, Dirk had to weigh whether it made sense for him to try to win a championship with a team that was coming off an embarrassing playoff exit, in his case to the Spurs in the first round.
That was just the latest in a string of disappointments. In 2007, the year after the Finals appearance, Nowitzki suffered the humiliation of being awarded the MVP trophy after his team was beaten in the first round by the eighth-seeded Warriors. In 2008, the Hornets beat Dallas in the first round. In 2009, it was the Nuggets in the second round. It had started to look as though it wasn't going to happen for the Mavericks. Maybe Nowitzki wasn't a true franchise player.
With the Lakers and Oklahoma City being obvious favorites to get to the Finals after the 2010 playoffs, a lot of people wondered whether Dirk would have been smart to pull a LeBron and pair with another superstar to increase his chances of winning a title.
But Dirk and LeBron decided to take different risks. And even though they both picked good teams, had they not gotten to the Finals, neither would have been spared ridicule.
Regardless, Dirk and LeBron have managed to create a paths that other superstar players facing major free-agency decisions -- Dwight Howard, Deron Williams and Chris Paul, for example -- should survey as they approach their career crossroads.
The lesson to be gleaned from LeBron and Dirk is simple. Sometimes you have to make a difficult decision to put yourself in position to achieve the ultimate prize.
Jemele Hill can be reached at email@example.com.