After the difficulty bomb last week ZEC has been a good 30% more profitable than ETH to mine.

This only matters if you are immediately selling the coins. For some reason people think that if they mine the coin while its most profitable they make more. This is absolutely not the case is the only number that matters is the price when you convert it to something else.

Then, of course, there are the people that just throw their money away using nicehash because they are too lazy to convert it for themselves.