I'm seeing 38% faster downloads from Phoenix (nearest CloudFront edge: L.A.). I ran 5 trials on a 178MB video hosted on S3 [1] and CloudFront [2]. The S3 GETs took: 6m02s, 1m50s, -failed after 28MB- , 2m01s, 2m04s. The CloudFront GETs took: 3m40s, 1m10s, 1m23s, 2m05s, 1m25s. Ignoring the failed S3 run, we can compare average client latency: 2m59s vs 1m50s.

[1] http://2008.s3.amazonaws.com/09/javascript.mp4

[2] http://d11tgpuxrsgxu4.cloudfront.net/09/javascript.mp4