Windows still just works. I've tried really hard to make the switch and can't.
Steam (or video card drivers?) still isn't good enough to get me to make the switch. I have a pretty recent AMD card that gets around 300fps on Windows with the recommended settings. The radeon xorg driver gets 30-40fps with terrible jitter and fglrx has too many bugs in general to make much use of. I've done a lot of searching and tried many things, nothing helped much.
I have wireless usb headphones and, for some reason, they really only work well in Ubuntu with Unity. As much as I hate Unity (it's un-user friendly, buggy mess), it's the only DE that allows me to easily select that output and has support for the volume wheel on the headset. I've tried several of the popular distros and DEs. As an example, the volume wheel works in Mageia, but it kicks me out of full screen mode. I can't even select the headset output through other DE's like Cinnamon or MATE.