Bitcoin for sure. Bitcoin cash and other similar coins are only made due to forks, or at least, are made as copies of Bitcoin. And as we all know, it's always the original that prospers. I am not saying that in consideration of the point of origin, like for example with NEO and ETH, many say that since NEO is the China copy of ETH that it's not better, I don't share that belief because copy or not, it has it's own technology at its back and it also has their own following of people who support them, it's just that people trust the original more.
100% Bitcoin. Even when Bitcoin Cash jumped so high after the Coinbase listing. Even when Roger Ver and his minions poured all their money into promoting Bitcoin Cash. Even when people said they would drop Bitcoin and adopt BCH. Nothing convinced me that it would ever sniff the success of Bitcoin. Everywhere in the world the old system is sitting up and taking notice of Bitcoin. Those who noticed BCH like in Canada even said it was a scam.
They might have done well as a fork alt, but they chose to do it in tasteless ways.