At least one person (me) is stuck on 10.9.5 because of audio / Jack Router. I have tried using a multiple-output device (actually, several of them; one as the default output, the others as program-specific outputs), only to find that at least in 10.9.5, multi-output devices that include an HDMI monitor will fail to work once the monitor is turned off, and then turned back on again (say, overnight / next morning).
Grumble Grumble Grumble Apple, you used to be the best-choice for graphics and audio. Now, your audio support stinks, and your graphics ... the inability to actually display what's in the picture (instead of a monitor correction of a picture) really makes things hard at times grumble grumble.