Nice. One way you could distinguish your service from all other options (S3, Github Pages), is to support the history API for single page webapps. I'm hosting a static site on EC2 instead of S3 because I need URLs to fallback to index.html. Literally for this one nginx rule:

    location / {
        try_files $uri /index.html =404;
    }

Also, I'd like to try the beta of your service, just signed up. My email is in my profile. Thanks!