Neon exchange will be one of top top 20 exchanges in one year, I am very sure because they are working very hard and their product is look very good for me. Maybe it will need some more time, because it is hard to get the trust of the people with a new exchange.
With 2 NEO co-founders on board, I don't think getting trust is going to be the biggest issue here. Although I do believe they will have to fight to get a portion of the market. I'm very curious to see how this rolls out to be honest.
I have a suspicion this DEX will do very well -- but I will choose to sit this one out and just do more of a "wait and see" stance instead of going all in.
I think the success of DEXes rest entirely on the failure of centralized exchanges. If governments start (or in some cases, continue) to crack down on/heavily regulate/shut down centralized exchanges, then by proxy decentralized exchanges will flourish. As long as centralized exchanges are viable options, I believe they will be the most popular ones -- meaning DEXes are less often used; hence, less successful.