Though the similarities are clear between these four, the debate of who is the greatest is one that should never occur.
Most people like to compare Lebron James with Michael Jordan. I honestly don't see the similarities. Sure they're both the face of the league in the respected eras, but the similarities come to a screeching halt after that. If you look at actual similarities that players have with one another, you will see that Kobe compares more to MJ and Lebron compares more to Magic Johnson.
Kobe and MJ
Killer instinct, cocky attitude, and a need for the ball when the game is on the line. Who does that describe? Kobe Bryant or Micheal Jordan? The answer is both. Kobe and MJ have many striking similarities in their game. Both have the killer instinct that's fueled when someone either talks smack or challenges them, both directly and indirectly. Both dominated a decade of basketball and were deemed (by most) the face of the league during their era. Not too mention, both Kobe and Jordan have a certain swagger about them. When they walk into the room, everyone knows they're the best.
Lebron and Magic
If I were describing a 6'9" facilitator with the ability to take over a game at will would I be talking about Magic Johnson or Lebron James? The answer is both. If you look at the style of play between Lebron and Magic its alarmingly similar. Both are smiling 90% of the time and love to joke around with their teammates, but have that competitor inside them that will take over the game in crunch time, you can see their demeanor change instantly. Magic and Lebron are also the face of the league. Everywhere you went you saw Magic jerseys, commercials, "swag" and you see the same, and even more, now with Lebron. Lebron and Magic are much more comparable than the tired MJ/Lebron discussion.
Though the similarities are clear between these four, the debate of "who is the greatest" is one that should never occur. These four were/are the greatest of their time and everyone should just leave it as that and recognize greatness as it comes.