Matt - Thanks so much for posting those videos. You can see how a spiral mixer is so gentle even at a relatively moderate speed. There is none of the smashing and slapping that happens in a kitchen aid. Also, I understand now why the double hydration is important - your mixing gets done more efficiently at the lower hydration, especially with the spiral.
As it applies to this style, I would suggest the spiral is more akin to gentle hand development over a period of a few hours, but gets the job done in a matter of minutes.
If you were choosing a spiral or fork mixer for general use, what would you go with if money and space were not prohibitive?