As much as I tried, there just wasn't any way of making the title of this post more exciting, however it is worth reading nonetheless

The UK licensing team has done a good job of trying to make it much simpler to see what Software Assurance benefits you actually get per volume licensing agreement. Many people assume Software Assurance is just about securing the next version of a product, but it has so many more benefits beyond this, including training and time with partners. These go right through from the plan, deploy, use, maintain and transition phase

There are 2 versions depending on the size of organisation you belong to:

Less than 250 PCs
More than 250 PCs