Interesting items in the product guide. The 49 page document focuses 100% on the touch / Start Screen (aka Metro) side of things. Right from the start (Page #5) they talk about how useful creating a Microsoft account is, and all the wonderful things that you can do with it. There is no mention at all about the option to create a local account, even though we all know you can still do that.
All of the focus is on the Apps that come either pre-installed, or ones that you can download from the App Store. Each of the apps that are pre-installed are highlighted (Weather, Bing Maps, Travel, and so on) and how you can use them to help you be more productive in your daily life.
There is no mention anywhere of any of the other new features of Windows 8.1, like the changes to the Windows Explorer (ribbon look), changes to the task manager, or any of the under the hood (so to speak) changes that were made.
The one thing that I do want to highlight here is that this is the first place that I have seen officially documented how to do things in the Start Screen without touch. Meaning, what is the mouse equivalent action for a specific touch item.
If you look on Page #18 and #19 of the Product Guide, you can see just that information.
For those that don't want to download and read it themselves, below are images from those two pages.
Page #18
Page #19
Finally, I want to add that out of all the screen pictures shown in the document, only 2 of them are shown in desktop mode. All the rest are from the Start Screen or Apps from the Windows Store. In fact, the Product guide does not even mention "Desktop mode" at all. It is almost like (at least to me) Microsoft is trying to not let people know that side exists in the OS anymore.
--Brian