Initially, this trade would not payoff for the Magic. It would probably take 2 years for them to sufficiently benefit. Why? Orlando would have a tough time surrounding Lebron with enough rebounding and defense, which he'll need to win in the playoffs. The Magic already have a thin front-court with Dwight on their team. Orlando is more fucked when Dwight is gone. Right now, Orlando has Gilbert and Hedo on the books making $30 mill/per combined. Those contracts are a killer. In 2 years, when Gilbert and Hedo's contracts are close to expiring and can be traded, then the Magic would be in a position to build a proper contending team. But, until then, Jameer, Lebron, and J-Rich, assuming he re-signs, would be left to try and out-gun the opposition. They wouldn't be left with other options for their style of play.
So, in the short term, I think Miami wins the trade because they would still be serious title contenders. But, in the long-term, I think Orlando could win the trade, depending on the other moves management makes and how quickly they get done.
Edit - and that's why I refuse to vote: none of the options represent my opinion.