You didn't even address the part about actually comparing security tests between yours and other exchanges. Now if you had done that and a 3rd party (neutral) claimed your site as "the most secure" then fine. But until then, it is just YOUR opinion as opposed to facts that you are advertising to users.
Typical salesman tactics...
Many companies/sites make claims about themselves which are very hard to verify. It is called marketing.
In this case many people who read about the security at mcxNOW and know the system do believe it is the most secure out of the systems *they know*. I am not the only one, and you can consider it an untested marketing claim / salesman tactic if you want, no one will fault you for that.