Personally I think anyone who says Jordan (or anyone for that matter) is the greatest player in NBA history is a sure sign that they haven't truly thought about it very hard. I don't understand how anyone can say, without a shadow of doubt, that any one player is the best ever, despite all the factors that make deciding it almost impossible.
How do you make up for the difference in eras? Mikan's era could not have been more different to Russell's era, which could not have been more different to Magic and Bird's era, which was very different to Jordan's era, which was very different to today's era.
How do you make up for the differences in postions? The centre position is a totally different game than the small forward. Point guard is totally different to shooting guard. I think it would be hard enough to say who the best point guard or centre of all time is, not to mention how hard it would be to say who the best player full stop is. How do you seriously compare Jordan to Russell with any degree of intellectual rigour? How do you compare Jordan to Magic? Or Jordan to Kareem? Totally different players, totally different approaches, totally different positions, totally different mindsets, totally different games.
Jordan and Kobe are probably easier to compare because their eras run side by side, so the game is not radically different. And they play the same position. I think LA Boy hit the nail on the head with his statement about Jordan going with the flow of the game and Kobe forcing the game. That's the reason Kobe's FG% is some times horrid while Jordan's rarely got that bad (though he had some shocking shooting games in the finals against the Sonics in 1996, but people forget that.) Kobe and Jordan are about the same in almost every other part of the game. The fact that Kobe forces his game is his biggest weakness. Perhaps his only true weakness.
So, I do think Jordan has the edge over Kobe but I think its very slight. But to say Jordan is the best player is just way too simplistic.