Inov-8 Insider,
You're right. It took me 3 months of training in order to be able to do a 5 km barefoot. And I had already a not too bad running form (thanks to some reading I had done - Gordon Pirie, Danny Dreyer's Chi Running...) The guys that sold me my 1st pair of shoes (that I trained with for my 1st marathon) couldn't believe I had ran more than 1 000 km with it!
I did some fellrunning and was experimenting with minimalist shoes this week! There is nothing as fun as running in mountain!
I tried some huaraches sandals, Vibram FiveFingers KSO and Mizuno Wave Universe 2. I really like the KSOs, I felt safer with it probably because my heel was closer to the ground than with Wave Universe. I am looking forward to get the hand on a pair of Vibram's Trek new model. It will give more grip for rougher condition. And for the huaraches as I had a too thin sole, it wasn't as good. In a less challenging trail like what I had last year, huaraches are hard to beat tough.
So for the conditions I had, KSO get the 1 st rank, Wave Universe the 2nd and huaraches the last (because I had a too thin sole).
If Inov-8 could manage to design a shoe with grip that has a flexible sole, a lower heel than my pair of Wave Universe with a decent weight I'd probably order a pair for experimenting in fellrunning conditions, for treking and backpaking.
Have fun running!