I have these shoes in both the red and the black/blue and I love them.  I'm extremely flat footed and have horrible knees.  I'm only 20 years old, so I refuse to give up on working out.  I had no idea the shoes I wear could make such a difference.  When I work out with different shoes I can definitely feel the difference.  I do cardio videos on a tile floor and these shoes have done wonders for me.  I've even stopped having to wear my knee brace since wearing these shoes.