I started using a method really similar to this to host a blog a few months ago, shortly after the S3 static website feature was released. However, shortly after a post ended up on the front page of hacker news, requests to anything on the S3 bucket started responding with 503 errors.

Not entirely sure what the issue was, since I use S3 to host static assets for other sites that see similar traffic levels, and haven't gotten any 503 errors. And clearly ATD seems to be handling the HN traffic just fine.