We used to sell both, but don't sell either right now. l would say that a well setup pair of the Ushers are an overall better speaker.
The DMD tweeter has wonderful detail and is very smooth and airy, and it is a better tweeter than the Adagios, the Usher midrange is clearer and they throw a very large sound stage.
The Zens are very competent speakers they are not as magical as the Ushers.
I