I am not sure if this section is the best to post such a topic.
I would go for Ethereum though as i am fascinated by the solid developers team.
NEO is still new coin and they need to implement many things and if they can able to implement all those features then NEO can give the best returns for investors. But as of now, ETH is best because it is already fully working model and many tokens are distributed on this network. NEO is Chinese product so if it is successful then most of the chines tokens distribution may happen on NEO chain. For investment point of view better invest in both of these coins because diversification always gives better profit then just investing in a single coin.