Admittedly, I tend to hang to old running shoes too long; first run in these I dropped almost 30 seconds per mile off my average.  I'm 6'3", 210 pounds and tend to have aggravating calf pain while running.  So far with the Kayano 17's I haven't had any calf pain, nor have I had any recovery issues.  I'm not comfortable recommending shoes as each person is different, but I'll purchase these again.