Yes.... It's worth it. I had mine installed by Sean when he was in town about a year ago. We are very satisfied with the results, as the Zu sound that so many said was lost, is now back, and very enjoyable.
I really liked the Essence as they were, they were missing some of what my previous Druids had in the upper registers, but the bass was better. They were very enjoyable, but now I feel that they are a great speaker. I believe that if they would have launched them like this, instead of the "dialed back" drivers (to mate up to the ribbons), they would have been a bigger hit.
The nano-tech drivers are something....