sorry for disturb you, but...
why we need NAV when it is monero and z-cash ?

what special in NAV?
Zcash has 20% "tax". If you want Zcash's anon tech, then go with Zclassic.
Monero uses ring signatures.
And NAV uses a subchain for anon, dont waste much energy for mining because Proof-of-Stake and has a block time of 30 seconds.
Each of them uses his tech and you can decide.