I have one as does my buddy down in SC. If you're running a large motor that has power trim/tilt, they will certainly save your lower unit. I have hit countless sandbars, oyster beds, and logs with it and no damage to my 40hp motor. Another benefit is that it gets the motor further off the back of the boat which allows you to raise it a bit. I noticed some improvement on my top end speed and hole shot as well.
Andy