The ability to set up multiple tests, each one of which can be run individually or in conjunction with other test types (A/B). It's easy enough to get started but there is some learning curve if you're not used to testing software applications. I've been able to use it effectively since we have an established ATS platform already so this has helped us move forward more quickly than would otherwise be possible without such tools available. We are currently using it primarily as part of our AB Testing process where we want to see how different variations perform against another version of our application. This allows us to make changes and then compare results immediately rather than waiting until after launch when things may change again.