I run and use Varia for training, especially during the invermal season when I train at night. I find it very convenient because you do not distract yourself to look the times or steps on 935 but you have that parameter to Varia. for the ride you have to use it with a run-hat or a elastic-band to avoid the bouncing of the glasses weighted by the Varia
Bought the Garmin varia vision, I will try it out on arrival, hopefully Friday. So far I can only use it with the Garmin Edge 1000. No compatibility with Forerunner 920XT, don't understand why as a SW developer engineer except for commercial reasons, as the varia vision is just a HUD needing to show metrics and no special processing required on the 920XT as all data is available...