Zcash is a popular cryptocurrency which has great privacy features. However, 20% of all mining rewards for the first 4 years (which is around 10% of the coin supply) goes to the devs. This caused a lot of anger in the community, especially when the price started rising a lot. In ZClassic, all rewards go to the miners. Other than that, it is identical to ZCash. It has the same security and privacy features, with some slow blocks being eliminated. This high level of privacy means ZClassic is fungible. This means no two coins can be distinguished. This prevents miners from selectively censoring transactions. This also reduces the impact of government controlled miners.