Definitely the Cartels. The C02's are stiffer which I didn't really like on the CusFly-V. To be honest, I didn't really like the Cartels either lol. However, I would choose the Cartels over the C02's. The Cartels are pretty stiff too, but I found the C02s to be a bit overboard in stiffness for the Custom Fly-V.
Great board though. Shred the ish out of that beast.