"Rackspace uses 213 of Akamai's edge locations, selected especially for our customers' typical usage patterns, and designed to cover all major areas of the globe." http://www.rackspace.com/cloud/files/
Akamai has approximately 5 gazillion edge locations, so yes, it is a cut down version. It is still a lot more POPs than just about every other CDN, though this doesn't necessarily translate into performance.
"though this doesn't necessarily translate into performance" - Yes, even when the files were already cached, I wasn't always satisfied with the performance.
A detail that bugged me, by the way, was the high number of CNAME requests, although this should at worst affect the first view.
"Rackspace uses 213 of Akamai's edge locations, selected especially for our customers' typical usage patterns, and designed to cover all major areas of the globe." http://www.rackspace.com/cloud/files/
Akamai has approximately 5 gazillion edge locations, so yes, it is a cut down version. It is still a lot more POPs than just about every other CDN, though this doesn't necessarily translate into performance.