I purchased a bunch of the mounts for about 25 cameras. I was very happy with the mounting mechanism, and the size of the units. They easily slip over the t-posts, and allow you to position the camera in an array of angles to frame your images well.
My only problem was that raccoons, deer, and cows routinely moved the arm of the mount. No matter how hard I manually tightened them, they could be moved fairly easily and I would end up with crooked photos. Ultimately, I would have to check the cameras twice a week to make sure they were taking pictures of the intended area instead of the sky or ground.
They're great mounts if you don't have high volumes of animals that could come into contact with them.