I've seen it. Eight minutes of not much. Bass great, treble good "yada yada" to use his words if you get a proper fit, mids questionable. Might as well go to the frontpage of his site and try to read too much into the sentence fragments he graces us with.
So the Z1R gets a grade of S= (by the way, I wonder if we'll ever get the One Punch Man of iems), highest one, but is listed toward the bottom of this top tier. The summary states:
Highly defined sound, realistic sub-bass focus and spacious imaging capabilities.
The signature is mild v-shape.
The Solaris gets an A=, which is tier four but there are a lot of tiers and these are still considered some of the best by many. He finds the Andromeda S to be better for whatever reason, getting a grade of S- or tier two.
Coherent and well balanced hybrid though with slight midrange hollowness.
Signature is balanced. So I might piece these two summaries to mean that the Solaris is all-around solid whereas the Z1R is just more advanced or refined (it's ironic how he mentions the mids of the Solaris critically but not of the Z1R). Highly defined sound and spacious imaging capabilities being singled out conveys better technical performance and design to me. Except this is the summary he leaves for the Andromeda S:
Highly coherent, easy-to-love tuning and spacious headstage
I kind of doubt Campfire made the later and more expensive Solaris less coherent with a soundstage we don't need to mention. Did the different treble tunings of the two trick him or give him that impression or sensation? I do know that at the other place we shall not speak of some agree that the Andromeda S sounds better (to them) and single out the effect of an airier treble, whatever that means. I've also seen it mentioned that treble can create the sensation of more space.