Imaging is one thing that fell into place with a SET amp for me, big time. It went from ok to speakers totally disappearing in the room. I think that is a sign if a good system, you should not be able to pinpoint the position of the speakers on a good recording.
2 way speakers can image really well, but if you optimize the system for a 2-way with separate tweet vs a single driver the single driver will win, hands down. The key here is optimize the system for the speaker, otherwise the comparisons mean very little. Your results will strongly depend on your choice of amplifiers so it isn't so east to compare these two speakers fairly. A SET will give the Omegas an unfair advantage while a more powerful amp will favor the 2-ways. For the most part... there are certainly many exceptions, like a good class A SS amp could work well for both. Anyway, just one thing to consider....