is the lack of updated drivers from the various hardware manufacturers. I have a Dell Inspiron with an Intel graphics card that I bought just last year. When I upgraded to Windows 10, it was having some serious issues with the display drivers. I ended up re-installing Windows 10 with a clean slate. Now I am unable to extend my display to a monitor via the HDMI port. I tried updating the driver through Device Manager and it alerted me that there was an error. I went to Intel's site to look for available drivers and the only driver they have for Windows 10 is for the 32-bit version. Microsoft released their preview builds for Windows 10 several months ago. Companies like Intel have had plenty of time to patch their software in preparation. This problem is one of the biggest reasons Apple generally succeeds where Microsoft doesn't. Apple controls their entire ecosystem so their perceived success isn't partially dependent on partners, like Microsoft's is in the PC world.