Iíve been using a RRS Lever-Release Clamp for nearly 4 1/2 years. Though my tripod has seen some pretty nasty falls, the clamp has never failed to function perfectly. I also own a PCL-1 Panning Clamp (which I use primarily when intending to stitch several photos together) and have found no real advantage to a screw-knob type clamp. Quite to the contrary, the Lever-Release is much faster as well as being considerably easier to use with gloves. Of course, it does require a RRS (...or Wimberley) plate. Like many, before purchase I had reservations concerning its long-term dependability. Gratefully, they proved to be unfounded.