...and are the trading competitions legit?
Do you mean this?
50,000 NewsCrypto (NWC) trading competition comingFor this trading competition, you will need decent funds to compete. If you have some coins already deposited on that exchange, it's worth to try. But if you are just a newcomer and just want to use the exchange because of the competition, I think it's not a good idea unless you understand the risks. About the legitimacy, they are
legit* but for the competition, no one knows if there are flaws in the process.
Any insight information about their real volume..
As for the volume, I can fairly say that is decent. You can check their exchange stats on some of the site checkers and do some comparison by yourself.
Crypto-exchange checkers won't just scrap random data somewhere so there is a valid source.