What speeds can I expect?
One good tool which you can use is our DNS debugger. For example, you go to http://debug.onappcdn.com/dns/ (type-in your resource ID), you can see the "selected" result, that would be the pop which serving the file to you, and its ping data.
It is difficult to give an estimation of how fast the download speed of a specific file delivered through the CDN. It depends on multiple factors. For example, the speed of the origin to the CDN pop, number of CDN pops that specific file is delivering to, cache hit ratio, the speed from the CDN pop to the end users, connect/response time of the DNS, etc.