I have a Sitecore installation in production. Most standard features are being used—Content Editor, Experience Editor, xDB, Experience Profile, Experience Analytics, MVC, custom pipeline processors, Lucene indexes, etc. We're also using a dependency injection container integrated with MVC controllers.
The Sitecore version currently used is 8.1 rev. 151003 (8.1 Initial Release).
The latest available version is 8.2 rev. 160729 (8.2 Initial Release).
What are the biggest benefits of upgrading from 8.1 to 8.2?