(CP ALERT)
Truthfully, on court skills and stats are very close between the two. The differences in various categories is very close, and there are hardly any stats where one is far and away much better than the other.
LeBron will pass a lot of career stats of MJ because he will have a longer career, etc. and the 'by the age of' comparisons are off as well, because LeBron started his career 4 years earlier, so by the age of, he will have had 3 more full seasons of stat accumulation.
Different eras, different style of play so frankly, any comparison between the two can only intelligently be debated in terms of how they dominated and performed against their contemporaries in their given era.
MJ was clearly, beyond a shadow of a doubt the best player in his era. The gap between him, Reggie, Barkley, Clyde, GP, etc. was a pretty big one. Hakeem was the only player who really could challenge MJ for 'supremacy' during that time in my opinion, and I'd still give it to Jordan.
LeBron is clearly beyond a shadow of a doubt th ebest player in this era. Lately, because of the hype surrounding their style of play, and his otherworldly shooting ability, Steph has challenged that title in some peoples minds, winning 2 MVPs, but anybody with any common sense could NEVER say he is a better player than LeBron... its not even close.
If you are comparing them in terms of skills, and on court PHYSICAL achievement, its very close, but at 6'8" to be able to do the things athletically he does, LeBron has changed the game, so as a transcendent player, to me, he is better. MJ on the other hand, did a lot of things never seen before, and captivated the sports world in a way that hasn't been seen before or after his career, and in a world with no social media the way we have it now, that is impressive.
When it comes down to winning, thats where the line is drawn. Two schools of thought:
1: 6-0, undefeated, 6 time finals MVP, cannot be disputed
2: 6 straight finals, 2 chips is very impressive. Win or Lose, a lot of HOF players never get to a finals, to go to 6 straight is damn near impossible and should be celebrated. It's frankly an achievement that I don't believe we will ever see again.
With basketball being a team sport, you cannot lay a loss on the head of one guy and qualify him as a loser because of it. (I know I fuck around and talk shit about LeBron, but thats pretty much all it is, talking shit!).
Its really pick your poison, some value longevity and levels of success over winning when you get their and being undefeated.
I'm of the school of though that, when you reach the top, winning, and being the best player on the court when you do when trumps getting their multiple times. So for me, MJ > LeBron, but is extremely close.
As much as I clown, I really don't disrespect or completely disagree for those who believe LeBron's body of work makes him #1. It's really a pick your poison conversation. I'm just glad to have been able to see the entire careers of both Guys, and to me, they are 1/1a in terms of the best players I've ever seen play.