Ah that's easy: market cap and potential ROI. The ETH market cap is already 20x that of NEO - limiting its growth relative to the lower market cap coin. NEO is very well positioned for any pro-crypto move on the part of the Chinese authorities. Da Hongfei has seen to that himself, even acting as an advisor to government entities. Of course NEO can be used by others too, but a crypto mad nation that's 1.5 billion people strong makes for an attractive first prize. Technology wise NEO runs circles around the other two as well as business wise.