Zcash requires a trusted setup. That's a huge problem. One of the foundational points of crypto is that we shouldn't have to trust anyone....only math.
A trusted setup also means that the Zcash team could print their own Zcash and nobody would necessarily know it ever happened.
Let's say that all of the Zcash core team is trustworthy. Fine, but it's still an assumption. Now, what if a hacker gained control of one of their accounts? They also could "print" their own Zcash without anyone necessarily knowing, inflating the Zcash economy.
Also, check out Zcash website and look at the loads of academic, government, and banking people involved with the project. To me, that makes them even more untrustworthy. Yet another foundational point of cryptocurrencies: you shouldn't need to rely on government or big banks, and Zcash has waded deep into both of those pools.
Bottom line: if you have to trust people, it's flawed from the start. You should only have to trust math.
Read more:
https://blog.okturtles.com/2016/03/the-zcash-catch/http://weuse.cash/2016/06/09/btc-xmr-zcash/Just go with Monero: open source, fully decentralized, no trusted setup, totally private, untraceable,and fungible.