Cavs do have Lebron, but the Magic have Dwight Howard.. who is also unguardable. The Magic shoot the three better than anyone else in the NBA (Rashard Lewis leads the league in 3's made). You can't base your analysis on just one player otherwise you would bet on Cleveland, Orlando, Miami,and the Lakers every single game b/c they all have a player that is unguardable.
+5 is a lot to give to the Cavs, but they are shorthanded and didn't fare to well against the Lakers a couple weeks ago when they were getting +5.