I place Bitnomial in-between good and bad because I don't really know or let me say, there is nothing much to say about the exchange. The exchange seems to be yet to be launched and so the information provided is very low.
From the little information the exchange has so far provided, it appears to be very legit with the exchange being approved by the CFTC and has made access to the exchange to be made available through a wait list and requires referral to go up the ladders to access the exchange.
The exchange is basically meant for Futures trading and derivatives and with the look of things, they will be offering a better service. Hopefully if I get access to the exchange via it's support team, I will be writing an update to my review soon