I am going to say that Monero is gonna hit $1Bn landmark before ETC does. Starting to get a sense that Monero may continue to have some relevance even beyond Z-cash launching. Privacy is hot.
I also have the feeling that Monero would somehow hit that mark due to people flocking around and getting deeper into the said coin. Too many contenders in terms of privacy, though, and I can't say whether XMR would come out as the winner in this privacy contest between different hot coins (ETH, Z-cash, name it).
I think the Monero can be the next billion dollar cryto currency. At the moment, it is about $180 million. It will take several years.