Is CEX.IO legit?

I've been hearing a lot about CEX.IO as a cryptocurrency exchange platform, but I'm still hesitant to use it. Can you tell me if CEX.IO is a legitimate and trustworthy platform? What kind of security measures does it have in place to protect user funds? Are there any negative reviews or complaints about the platform that I should be aware of? I want to make sure I'm making an informed decision before investing my money.