Probably nothing but RW posted a review in their mag saying 2002 was a cosmetic upgrade to 2001 which was a pile of tosh. They had completely changed the toe box, gullies, etc and for a wide footed, high instepped runner like me it was a disaster. I gave up on mine, begged for my money back and went back to Sauconys. However, I've heard that these Rider 6s are due out and would like to see some more detail. My Rider 2001s are hanging on in there but no use at all for long runs. So this is just my personal opinion - nothing professional but still interesting to note that they appear to have considered some customer feedback.