I am a huge disc fan: I played Ultimate for 15+ years and I have a now 9-year-old Aussie Shepherd who is a disc champion. I test every disc from every dog-toy manufacturer. I had great hopes for the Zisc, as I do like the Zygoflex material. However, the weighting is not great. Overall, it is too heavy to be truly aerodynamic. Moreover, the shape needs improvement. The weight should be focus in the rim of the disc. Currently, the Zisc is same thickness all over. Also, the outside of the rim should be curved to improve its flight.
I do like the Zisc, but it is not my current disc of choice for my daily disc use with my Aussie.