I think the trap people fall into with ED, is that they think since the acceptance rate is higher, they are more likely to be accepted with slightly lower stats. At the very very selective colleges, that is not the case for the unhooked applicant. And at small schools, where hooked kids make up a bigger percentage, it definitely is not true. A non-hooked ED app must be very strong to get in to a highly selective school. But once you move past the Ivies and the top 10 LACs and other tippy top universities, the ED bump is more real.
When schools have both EA and ED, the EA results can be hard to predict.