The coin may have good developers, but that makes almost no difference if the coin itself has serious flaws. Piggybacking on hyc's comment above, the coin can't be considered to be private due to several factors:
Zcash requires a Trusted Setup. This means that you have to trust that the Zcash system was set up without any backdoors, potential for eavsdropping or monitoring of your transactions, or any other nefarious purposes. As we've seen with virtually all large software companies, such as Microsoft, Apple, and even governments, they can't be trusted. Trusting people you don't know in those positions makes no sense. Trusting in only math is better.
A Trusted Setup system also means that the Zcash developers could produce more Zcash at any time without anyone knowing (
https://blog.okturtles.com/2016/03/the-zcash-catch/), thus inflating the Zcash economy while making themselves rich. If a hacker gained access to the system, he could do the same thing...and nobody would necessarily know. Look at the comments at the bottom of the okturtles article and see how the Zcash team evaded answers about this. Their not giving a straight answer after several attempts to get a straight answer only fosters more doubt as to their trustworthiness.
Despite all of the famous academic, banking, and industry personnel involved with Zcash, it seems to have serious trust issues, especially for an open-source project. As you can see from their backgrounds, some of them come from banking and government, both of which have earned the reputation of being untrustworthy. Why would you want to trust your private finances to an organization led by people with those backgrounds - the same organizations which want to control your finances and restrict your privacy?
See also
http://weuse.cash/2016/06/09/btc-xmr-zcash/ 
