Being a large man suffering from plantar fasciitis in my left heel and knee issues, the Zigtech shoe line has proven to be a lifesaver.  This is my 8th pair of Zigtechs and my first ZigRhythm.  Like the Zigdynamic, this shoe protects my heel and puts a spring in my step.  I have recommended these to friends and have 2 that now swear by them as much, if not more, than me.  This shoe has no cons.  I just wish it came in a white color scheme.