I'm not sure what you mean about video and sound. OpenGL is first class on Linux distros, sound is almost exclusively pulseaudio now...and X11 is on its way out, hopefully it'll be dead to most desktop users within a small number of years.
Video on dual-screen setups is a bit wonky. Yes it's my fault for using crappy proprietary ATI drivers but try to explain that to someone new to Linux.
I have two issues with sound: 1) Sticking my headphone connector to my laptop's headphone jack does not work. I have to reboot in order to get headphone sound (works on Windows). 2) Connecting my PC to my TV via HDMI and playing a YouTube video ... Last time I heard a scratchy sound like that was when I tried to play a heavily damaged 45" record on my parent's turntable back in the early 80s.
I'm curious when the last time you tried Linux was? I used to have these issues in 2011 which is why I stuck with OSX, but now I use Linux exclusively because these problems are non-existent now.
