Originally Posted by
cyccommute
I haven't tried the Shadow but I can see the appeal for off-road use. It might even shift a little quicker. As long as it is high-normal, I don't see any issues with it. Probably not even any issues with low-normal but I'm not a fan of those. The price is right for either. I've Shadow XT and non-Shadow at Icyclesusa for around $55. That's dirt cheap for an XT.
The going theory on low-normal derailleurs, aside from if you snap a cable you still have a useable gear, is this:
The spring tension is pulling to the big cogs, and shifting off-road (or under touring load) to an easier gear will be improved. Faster downshifting means less time on the hills "easing up" on your pedal stroke to change gears.