Linkster: I heard the Eidolon & the Ceramique -- but on two different occasions, and only playing a Burmester test cd on both occasions...
With this limitation in mind, I respectfully submit that my Eidolon "musical experience" was superior to the one with Ceramique. The overall musical / tonal accuracy is what I'm getting at. I particularly found the E's upper register more extended, and the feeling of space more apparent. I can't single out bass performance per se: maybe the differences didn't strike me, or (probably) I missed them.
Let me add, in concluding this inconclusive diatribe, that the equipment on both occasions was mid-range Burmester & the cabling Nordost (valhalla), that I listen to classical & jazz (hence "listening" biases), and that I generally like & enjoy Avalon products anyway! Cheers.