This is my third pair of Fit Flops and I just love them.  They are the most comfortable shoes I own and I dread winter when I can no longer wear my sandals.  I don't believe they give you a "workout while you walk", but they definately absorb the shock to your knees & back very well and you can walk all day in them without being uncomfortable.  I've never much cared for thong type sandals, but these don't rub you raw between your toes. They hold up very well too.  I've had one pair for 4 years and have worn them alot, and can just wipe them with a damp rag and they are looking as good as new. Amazon definately has the best price on these. I would highly recommend these!