W3 Total Cache is the best caching plugin for WordPress at the moment. I've been planning to get on the plugin for the past many months. We had planned all sub-domains for using as in-house CDN and all other required folder/sub-folder. But couldn't do so, as the new year begin with the sad demise of our beloved father Shri Govind Ram.
To illustrate, what the W3 Total Cache offers, watch the video embedded below: