S3+ has multiple locations, but it uses the multiple locations AT THE SAME TIME, it is like a mini CDN, unlike S3 which is only delivered from a single location.
Amazon DOES charge you for transfer between S3 and Cloudfront... you have to pay transfer TO EACH EDGE SERVER at standard S3 transfer rates.
SimpleCDN's S3+ service is much cheaper than S3, with the same pricing for storage and $0.059 for transfer.
The other points you are missing are FEATURES. SimpleCDN supports RTMP streaming. HTTP streaming of FLV and MP4 files are also supported. As is gzip compression (A BIG Bandwidth Saver - 60% to 70% size savings on CSS and JS.) and the ability to set expires headers.
S3 and CloudFront does NONE of this. Repeat, NONE of this.
So lets say you had a website with lots of scripts, images, some videos, etc. So lets say it is 10GB worth of stuff. $50 a month for storage. Okay that is more... but then if you are pushing 10TB per month, that would be $1700 on S3, and $890 on SimpleCDN. So big deal for the $50. Plus gzip compression will save you more.
Did I mention RTMP Flash streaming? S3 is like something out of 1999.
Oh and SimpleCDN will mirror files from ANY HTTP website. With CloudFront you have to use S3. AND pay for S3 transfer to CloudFront. Stupid.
How often does CloudFront drop its cache of your files? Think about it, ALL CloudFront locations constantly caching your files and re-caching from S3, costing even more bandwidth. Stupid.
That makes Amazon THREE TIMES more expensive.