Been reading up on nxt and the ardor launch. how is the ardor different from nxt or ethereum? i like the childchain concept.
Ethereum has no child chains. But it has turing-complete smart contracts.
Nxt 1.x has neither child chains nor turing-complete smart contracts.
The only cryptocurrency project that has some similarities to Ardor seems to be Lisk, but Lisk's "sidechains" are probably less integrated into the main blockchain than Ardor's "child chains". The Ardor child chains are very tightly integrated one with another, because they can all be used for asset and currency trading and assets and currencies are global. I think with Lisk that should not be possible, but maybe I'm wrong.