Board Thread:Questions and Answers/@comment-25013293-20140227054301/@comment-26484417-20160227150412

The thing with powers of this grade is that it's no longer really a matter of "who would win if you pit them against one another", because simply the one to strike first would most likely be the winner. That's just how powerful these powers are, however, there are other ways to compare the two.

On the one hand, the description of Aether manipulation suggests this power is limited to manipulating Aether and any related power or magic, but has no control over--at least--the Nether and any related power or magic. On the other hand, Omni-Magic appears to be limited only by the the taxonomy of "magic". Based on this alone, I would outright say that Omni-Magic is superior to Aether Manipulation.