Over the last year CloudFront charges did increase but still reasonable (in the $50 range usually). Since the users of my app are all around the world having a solid CDN was key, but what made me decide to stick with CloudFront was all the third party API/client lib.
If someone can point out another good CDN with good API/client lib (python/java) that can make me reconsider my current CloudFront usage.
http://aws.amazon.com/cloudfront/faqs/#Can_I_choose_to_only_... expensive_Amazon_CloudFront_regions
http://aws.amazon.com/cloudfront/pricing/ (reserved pricing and price classes at the bottom)
But I've used maxcdn[1] before but they seem to have changed their pricing recently, but they do allow you to pay upfront and they do email out cheaper deals about every month for large-ish amounts (5TB and up).