Greg683x - Roy Hobbs beat me to the quotes (Cheers, Roy!). And I want to reiterate I'm not taking away from Marion's ability. He can play 4 positions and he brings a very unique skillset to the game.
But I lived in Phoenix in the time leading up to his leaving, and the local papers often jabbed at him (often unfairly, but with a basis in reality) for his attitude. A lot of people think, if not for the Suns being absolutely ROBBED (in my humble, and correct

opinion) by the referees in that San Antonio series a few years back, they would have gone on to win it all. The ring would've kept Marion quiet and maybe Shaq would still be in Miami, and Phoenix might have a pair of rings.
But ultimately, his bickering in the locker room was the catalyst that killed the fun suns and gave us the new suns. And I can't seem him succeeding in a situation like in Cleveland where not only would he be asked to fit himself into a system that revolves around one player, but he'd be doing it in a market less loving than Phoenix, in a region less pleasant to live in (I live in Ohio now... my lord I miss Arizona), and for a team that is under constant media scrutiny. Or rather, one player is.
It takes a special kind of athlete to be able to thrive as the second star in an environment where they know they aren't it. These guys have spent their lives being the Alpha dogs. It's different for a career role player, they grow into that position. I think that's part of what has made Cleveland's road so difficult, and their front offices job so hard. And it's why they still do not have a defacto #2.
Just my 14 cents.