I think what people are trying to say is, you don't need parkour-specific footwear to train. For more discussion on this, check out the shoes thread.
As to the Ariakes, I have a pair and I feel they are worse for parkour than the running shoes I wear. Aside from mediocre fit in critical areas, I don't think the rubber is that grippy, they show a lot of wear and the trade-off between feel and cushioning seems to fail on both counts. That said, I do like how they look and that's why I got them- comfortable enough and easy to slip on/off going through airport security. I think when K-Swiss did that promo event a while back, the coupons were for Champ's, maybe they still stock them.