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I would hold off on SRing until we have confirmation on it's stats. I haven't SRed the Zygarde in my X game I started 2 years ago waiting for this moment :O
I actually like 50% forme better than the perfect form. The perfect form doesn't have as much green parts and I kind liked the asymmetrical look 50% Zygarde has with the green and black hexagons. The prefect form is mostly black and has red an dblue that doesn't blend well with the design.