Zu Druid upgrade kit

Thank you, that has been very helpful. May I ask which amp you are running on the Essence (and have used on the Druid)?

I was using a Nuforce IA-7 integrated on both the Druid and the Essence. Now have swithced over to a Cayin A-50T tube amp with the Gold Lion KT-77 tubes. This amp is soooooo sweet with the Gold Lions. It can be found under 1K used here on Audiogon. Nice match with the Zu's.

The Essence is a killer. Love it with all sorts of music- jazz, classical, rock. It's a great all around performer.

The answer to your question may depend on your listening preferences and your amplifier. I purchased the Druid IV in 2005 and upgraded to the 08 drivers in 2008. The 08 tweeter produced more resolution and extersion in the highs, creating more transparency. The soundstage was wider and deeper creating a more immersive experience. The bass was also a little stronger. I was very pleased with the upgrade. The rich and dynamic Druid sound was retained. I still wanted better highs with more output, refinement, and extension, so last fall I purchased the Essence in pursuit of better highs. The Essence has a different sound than the Druid. It has far more output in the highs, which in my system was slightly too much on some music even after a lot experimentation in placement. The lower sensitivity, combined with my low power amps (Manley Retros with two 300B tubes per channel and about 15 SET watts) resulted in somewhat reduced dynamics versus the Druid, and I also heard less resolution in the midrange. The overall sound was a little less rich, probably due to the greater high frequency output. The soundstage was huge. I listen to a lot of rock/blues and really missed the dynamics and midrange resolution. It may have worked a lot better if I had a more powerful amplifier. I decided to keep my amplifier, sell the Essence and go back to the Druid, which I am still enjoying greatly. Of course this is just one opinion. Others obviously feel very differently. You may want to research other threads on Audiogon discussing the Druid vs Essence question. I believe that contributor Cobra 213 nails my perception of the differences.