Now there are absolutely no obvious competitors for ETH. Only in the long term such results can be achieved by ADA and EOS projects, but they are still at the initial stage of their development.
The base platform of Ethereum is sturdy and better than a lot of cryptocurrencies wanted to compete to Ethereum. But nowadays, it does not mean Ethereum does not have any competitor has power, technology enough to against it. Example NEO and Ripple, both coins have users sufficient to compete Ethereum any time. The fields applied to use both coins are many much. Even, it can be more than Ethereum.