I have been using rackspace cloud storage as a CDN for my site for some months. Before moving to rackspace I first used Amazon S3 and my overall experience is amazon S3 is slower than rackspace. Some of my senior brothers also told me that, but I first didn’t believe them. But practically when I used s3 I found its not working faster. And then I moved to rackspace files and it loads really faster. That’s why I suggest my blog readers and clients to use rackspace cloud files.
Amazon opted to build their own content delivery network (CDN) while Rackspace chose to partner with Limelight Networks, a leading, global CDN provider. Limelight serves some of the largest media customers in the world (including Disney, MSNBC, NetFlix, Microsoft Xbox, and Amazon Video on Demand) and has an extensive world-wide network. For a brief comparison read this article.
If you have wordpress powered sites and want to use CDN either amazon s3 or rackspace cloud files, then you could easily integrate them using the following plugins.
I’m using CDN Tools and its an excellent plugin. Just install the plugin and configure it by providing your rackspace cloud username and api key. Then by clicking Load Attachment your existing static contents will be uploaded in rackspace and on the fly the static content will load from cdn. You can also disable the feature when you want. And another good option of this plugin is that it uploads files side by side. So when you upload your files in wordpress this plugin copy the file in rackspace. So if for any case you don’t want to continue with rackspace, you can just disable the plugin and the static content will load from your server again.
If you want to integrate Amazon S3 in your site then you can use W3 Total Cache. This is also a nice plugin but it doesn’t support Rackspace yet. You will get brief information by visiting the plugin page.