Reasons I prefer Monero to Zcash:
Zcash has 10% premine (20% of the first 4 years production).
Cryptography of zcash is completely new and untested, compared to Monero being based on cryptonote which has a couple decades of academic research and testing.
Zcash requires you to trust the group of people creating the genesis block, forever. If they have actually colluded, they control the coin.
If Zcash ever has a bug which creates a large number of coins, there is no way to know, EVER. Because you cannot tell any info about the blockchain. The bug exploiter could gradually dump extra coins on the blockchain for all time, and you would never know. You ill never know if that downtrend is just a downtrend, or if some guy broke zcash and he has a quadrillion of them now and can dump infinitely.
But I'm in Monero, so therefore I am required to think Zcash and Dash are both scams.