We rode this yesterday and it was the highlight of our 5 days in PDS, second being Col de Coux/Arrete Berrois (thanks to @Ambrose and others on another thread). Stunning views and riding. We are guessing around 1100m descent.
@freeride, very good your tip to ride up the road, took me a few mins research to get the joke 😳 we booked a taxi pickup to return to Morzine although it may be possible to get a local Samoens company to drive you back to top of Col where you can ride back to LG/Morzine.
We made a small tactical error in deciding to ride / push up an extra 250m to high lift above Joux Plane only to find a very sketchy carry all the way down. Road from top of LG definitely the way to go. Short link to Borgouise very rutted from cattle. IGN map was essential and turn off track at Chantermele wasn’t marked and lower VTT route sign had no number. Printed directions from here plus map worked well. Thanks