The main pain point and the reason why we are moving to Fastly is that Cloudfront does not pass Cache-Control header to the browser by default.

Why should I care about this?

If you run a site that gets 2000 visitors per month, you probably don't. Cloudfront works great and you shouldn't care. However if you are anything like us and have to serve 1000000's of asset requests per month for awesome users, that rely on your service, then you do.