I didn't see any familiar names on the tramway segments in Strava but I did the lifts last weekend (slowly) and the tramway today (not as slowly, but we're talking decimal differences here).
Any discussion of comparative difficulty is probably compounded by the fact that you have a lot of climbing in your legs before you even get to the village, much less the lifts, whereas you can start right off with the tramway.
I will say the tramway is incredibly deceiving - the whole earth is tilted up about 10% there, so it looks relatively flat. But it's not.
I'm also starting to think that my garmin under reports slope. I know it's buffered and late to change, but I never saw anything like 15% on the ski lift road (despite cal trans signs to the contrary) and today I think my garmin topped out at 14%
OK - different question - for those of you who have done either of those two roads, how do they compare to Onyx or even 39 all the way up to 2. I'm assuming (hoping!) that they're more like GMR, just longer. Really longer.