Which are the best competitors to Ethereum, and why do you think so?
(I know on top of my head that Cardano and IOTA try to challenge Ethereum,
although they still haven't proved much from my understanding?)
If you are just pertaining to the cryptocurrency ETH, then maybe ripple Iota, cardano is good competitor, but seeing the capability of Ethereum as a whole is just to huge compared to other coins in the market as it has its powerful smart contract that provides opportunity for new altcoins to join the market and provide opportunities as well.