Gotta give a shout to fellow runners about these shoes. Brooks was cautious about jumping on the minimal sole bandwagon. Seems they listened to runners and created a shoe that takes the essence of the hype generated by Vibram et al and blended it with what runners need. I bought the Pure Flows... 4mm difference between heel and toe, designed to promote midfoot strike, 8.7 ounces. I've only run in mine once, but I love them. I'll share more long term data as I train for marathon in these shoes.