I have been mining Ethereum with Gtx 1060 6gb cards for three months. Due to the recent outrageous difficulty increase, I finally decided to switch to Zcash. According to mycryptobuddy, ethereum mining with current prices with a single Gtx 1060 brings $30 monthly, while Zcash brings $37 and Monero $25. This calculation may change in any time with a change in coin prices, that's why I am planning to decide which coin to mine in weekly periods.