The main problem with exchanges is scaling. Do these people know how to have like 100 servers connected together to handle millions of users?
Well there is no clear answer for that, we will see it as they open gates and start gaining traction (if). Bittrex did a good job on scaling so far, but I have some problems with the UX on both Bittrex and Poloniex from a trading perspective. Hope since this one is being founded by traders that they will have a nice UI and features.