Use them for light running and training. 1) Biggest problem, the side of the boot hits my ankle. There's a curve, but it's in the wrong place. (I think I have fairly normal feet and haven't had this problem with other NB models.) 2) The thin tongue folds easily so you often have to smooth it out when putting the shoe on. 3) After a few months, the flat, thin insole began to slide backwards, creating a gap of about 1-2 inches at the front and the heel cup getting stuck behind the heel. Removable insoles solved this problem, but now the overall cost of the shoe has increased. I've been a fan of NB shoes for a long time, but I'll look into other models.