Yes i have, heel strike to mid/forefoot strike. Don't think that the more you get up on your toes the better it is, because it isn't. People who mince around like they're tippy-toeing over hot coals are doing it wrong, look at videos online of African kids who've never worn shoes running, this is a far better example.
It feels at first like you're going to trip over and your feet will scuff hard as they land. Start by alternating it with your usual foot strike as it will load up areas that have never been loaded before. Plantar Fascia, Achilles Tendon and Achilles Bursa will get a big step change in loading. It didn't cure my knee problems by a long shot, but i know there have been changes in muscle recruitment in the quads.