I play without vibration dampener. This way I can get fuller acoustic feedback and I like to feel and hear all the vibrations of the frame and strings. To be clear, I'm talking about solid frames with good plowthrough, capable to respond with "good vibrations" to the good technique. Playing without vibration dampener, it feels easier on my arm and safer too. Maybe it's because I'm more careful to hit the "center of percussion" and get that special "sonic boom" without unpleasant distortion, or maybe dampener simply stiffens stringbed a bit. Besides, in order to hear and feel the vibrations I must hold racquet very loose and have very relaxed/smooth swing. Otherwise, if I hold it too tight, then my hand works as a vibration dampener and I don't know what does more harm to my arm: those tiny vibrations or simply being stiff and muscling the ball and/or squeezing the handle to stabilize racquet on off-center hits. The idea of vibration dampeners making racquets more arm friendly seems ridiculous to me, and not just because it does nothing to absorb shockwave. If energy is not dispersed in free oscillation of the strings, then where does it go? Arm is on the receiving end of all the "muted" vibrations, so I would prefer shockwave to be converted into vibrations of frame and strings, rather than be "comfortably" transferred into my arm. And, by the way, I did not see any "dampener" technology of late that translated into health benefits. I mean, Amplifeel and Innegra are presented to enhance feel and/or "comfort", but they are not marketed as "arm friendly" in terms of less shock to the arm. Lightweight and strong composites can improve "stability" of the frame, but only extra mass can actually "absorb" the shock. Otherwise the energy from the impact needs to be converted/dispersed into vibrations. Good vibrations.