You don't provide any valuable information why you might choose either speaker. What are your priorities and why have you landed on either of these?
My Nines had great tonal balance, timbre was top notch, and they were very easy to listen to. Also, and perhaps important to some, a good friend of mine is a luthier, and builds some really nice +$20k string instruments. He always asks me, throughout all my transitions....why did you get rid of those Devore speakers?
I've heard most of the Zu speakers and there is something about the cone design that I just can't handle. There is also a certain mechanical sound that never blends into the music. It's kind of like the tube vs. SS or digital vs. vinyl debates.
On the other hand the Zu speakers are really powerful, image extremely well and have dynamics like few others. It's all a balance but to me they seriously lack emotion.
You need to listen to them because you will be living with them.