Too bad there aren't any mining calculators out but it seems that most likely sometime in the next 24 hours mining ZCASH will be as profitable as ETH with GPUs.
With 1GH/s of ETH results in 0.0875 BTC at current difficulty and price.
Assume 1GH/s = 1kSol/s
Current network hashrate is ~275,000 Sol/s according to the block explorer.
Current block reward is 0.80 for miners. 576 blocks per day * 0.80 = 460.8 total ZEC mined. I will ignore the small increase in block reward size.
1000 / 275000 = 0.00003636 * 460.8 = 0.1675 ZEC mined per day.
At 1 ZEC/BTC thats 0.1675 BTC per day.
So its twice as profitable BUT keep in mind that
Pools arent stable
Miner software crashes
ZEC/BTC is very volatile
ETH difficulty might decrease further