Not the Omen but the Essence was measured by Stereophile (link below) and they are by far the worst measuring speaker I have ever seen them measure. I have never heard anything by Zu, just read the reviews...
"In many ways, the Zu Essence is an underachiever, measurement-wise. But the surprise for me, when I auditioned it in AD's room, was how much of its measured misbehavior was not too audible, other than the rolled-off highs and the lack of impact in the lower midrange."
http://www.stereophile.com/content/zu-essence-loudspeaker-measurements
"In many ways, the Zu Essence is an underachiever, measurement-wise. But the surprise for me, when I auditioned it in AD's room, was how much of its measured misbehavior was not too audible, other than the rolled-off highs and the lack of impact in the lower midrange."
http://www.stereophile.com/content/zu-essence-loudspeaker-measurements