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?)
NEO is a competitor that can compete and defeat Ethereum. NEO has its foundation and ecosystem that supports any tokens that want to grow on its basis. The NEO platform was chosen to develop tokens of multiple projections, and this helped its price rise to compete with Ethereum.
Yes I agree, if there is one coin that can compete the ethereum, I think it will be NEO. Because it has more advance technology that can compare to ethereum, it has its own platform also like what ethereum have. And the best thing asbout NEO it has a solid community that is the same with bitcoin and ethereum.