done it 3 times, will be there next saturday. Not much climbing, but what there is tends to be steep (granny + biggest on back).
However, if they stop the lifts due to storms (which are forecast), and you’re on the wrong side of the range and have to ride over either the col de cou or the col de chesery, you’re faced with a 1000m climb whichever way you go. I’ve done it a couple of times and I wouldn’t want to do it with heavy wheels – it takes hours even on XC wheels.
TBH it’s an XC event, this will be my 4th time on my old (single pivot) mount vision and I’ve never really wished for anything with more travel. After all, the route keeps you off the really tough stuff, and there is a lot of contour pedalling on the Swiss side.
Enjoy – it’s the highlight of the MTB year for me.