Windows 8/8.1 provides more options for the user, especially in the look and feel of the OS and as already mentioned it crosses device platforms (desktop, tablet, phone). With Win 8 you have the option of using the apps and downloading more apps from the MS Store as well toggling between the Metro/Modern interface and the desktop. Live tiles on the Metro interface are also handy at times, especially for email and social apps. But of course this all personal preference.
Win 8.1 provides more customization's for you than Win 8, such as booting straight into the desktop rather than the Start Screen. It also has SkyDrive (MS cloud service) built into the file system, which is handy for me if i want to quickly save docs in the cloud. Also, the Start button (although limited compared to the Win 7 and XP version) has returned with Win 8.1. However, if you want, you can replace this start button with some third party software, such as Start Menu Reviver, to make it more functional.
My screen is not a touch screen, but I have found that once I knew how the navigation works, especially with the Charms Bar, it didn't take long to work things out with a mouse and keyboard. The scroll wheel on the mouse is also helpful.
For more of an insight into Win 8.1 and the customization's that can be achieved, I have uploaded a number of videos to my YouTube Channel
TutevoTech if you want to check them out. These videos focus mainly on the customization's that can be done and give an introduction to some of the apps and SkyDrive.