I have purchased dozens of New Balance cross trainers over the years, begining with the 601 or 602.  In my view, each new model was an improvement in comfort and stability.  When I began using the 623 I recently bought to replace my worn out 622's, I could not believe it.  Compared to the 622, this shoe is lighter by at least 2 ounces, less sturdy, has less heelshock absorption, and has less support for the front of the foot.  I took several painful 3 mile walks before I decided to toss these 623's.  These shoes were a waste of $60.  622's seem to be in very short supply on Amazon and elsewhere.  I hope this does not portend discontinuation.  If so, I'm going to start stockpiling 622's.