Without being able to see the site, just a guess-question here - but how does this compare to FullContact or Refresh.io (recently sucked up by LinkedIn)?
We're always happy to see more companies set up shop in this space. It helps to keep us on our toes.
At first blush, it seems that EveryoneAPI is focused primarily on phone numbers. Conversely, our focus with FullContact is much more in line with social profile and public social data. Though you certainly can query the FullContact Person API via a phone number, that's never been our primary focus.
With relation to the comment about speed, it's worth noting that greater than 95% of Person API queries are returned in 30ms or less. But to the end user, depending upon where they are hosted, network latency can play a large role in the actual response time, which is a factor for any http based API traffic.
Like EveryoneAPI, we prefer to compete on merit rather than slinging mud. If you have a project that you're building, I'd love to see how we can help. Our APIs are always free to get started, so you can see your results before ever having to pay.