Sounds to me like a product that is only designed for really smart people...
No, I'm not making an appeal to authority. Sorry if it sounded like that.
The team behind Zcash has serious technical chops, and it's worth pointing out that some of the most competent cryptographers and engineers in the world are working on this project.
They've openly published the paper behind their protocol and their code base is open source. They aren't going the "trust us, we're kind of a big deal" route.
If you want to understand, read the paper: http://zerocash-project.org/paper
...and the source code: https://github.com/Electric-Coin-Company/zcash
If you don't want to bother to understand (e.g. if you don't consider yourself a subset of "really smart people"), then you have to find some other metric to decide whether or not to trust it. I offered the backgrounds and reputations of the people involved as one possible heuristic, but feel free to choose another if you prefer.