Hi Mike
Express is essentially Web Accelerator with Core Web Content Optimizations only. Express provides a safe set of website optimization features (HTML or URLs are not modified, only the page content itself ) that speed up page load times, shrink data sizes, and reduce bandwidth costs, without the need of any configuration. Express can be simply Enabled or Disabled. See more technical information here Aptimizer Express Add-on for Stingray Traffic Manager 9.5
Standard , also known as Enterprise edition is the full featured version of the Web Accelerator. All Web Content Optimization (WCO) features are available and configurable at a granular level. You can create custom rules based on Regex and wildcard URL path matches, these rules include optimization include/excludes, file merging level, cache duration, advanced image optimization and more.. This full featured version also includes pre-configured SharePoint 2007,2010 and 2013 profiles. This is the best option for SharePoint application and for user who want total control of WCO
Hope this helps,
