If fast boot works well on your system, it's definitely a reason to upgrade, but it looks like it isn't. The multiple desktops feature is also really nice. Direct X 12 is another reason to upgrade which you already acknowledged, but I won't be able to utilize it until I upgrade my graphics card. I have had no problems regarding the operating system itself. It's snappy, fast boot works well, all of my drivers work with it, etc. However, I could not upgrade by computer even after uninstalling my antivirus and as many programs as possible (I just left Visual Studio 2013 Ultimate and a few other programs because it would be too much trouble to download them), so I had to back up my files and do a clean install of Windows 8.1 with the product key, update it (which took forever), upgrade to Windows 10 using Get Windows 10, download a Windows 10 ISO, burn it to a disc, format the upgraded Windows 10 installation and install it using the disc, then install all of my programs again. My files didn't pose that much of an issue because I didn't have many.