I'll pop in here.
Steve Crandall of Ashaway just visited TW and I interviewed him on MonoGut ZX. You might find this interview
I'll let Chris add to this, but (as I recall) ZX MonoGut was a little too lively and unpredictable for him. He seems to prefer stiffer/deader polys, so ZX was not a great match for his stroke style. We have no immediate plans to review it.
The stiffness results from TWU lab are very interesting. Hope this helps.