dminor 

I've had four inverted forks (well, all the same make, just different model years) and I never experienced flex in them. Maybe I am not the most subtle detector; but at the time I was running them, I was still working on my jumping skills. I had a lot of off-kilter, blown or near-blown landings, off-balance nose-downs and such and the 8" just absorbed and sucked it up and forgave my mistakes more times than I care to remember. I also don't think I ever had the sliders twist in the triple clamps in a crash.

I do know, though, that Shivers had a widespread reputation for being flexy.

But inverted technology is the preferred method for off-road motorcycles now; it's so far along that there is no reason for an inverted bicycle design to be flexy if done correctly. The larger diameter structural members are the longer ones, so should impart better rigidity. The 'right-side-up' design is as quaint and long in the tooth as the venerable Cerrianis on my old flat track frame.