I have one - but mine had an unfortunate incident, and I've not used it since.. One of my camera bodies dropped to the floor.. I'd tightened the screws as usual before leaving the house, but was walking through a particularly busy central London event.. Three hours later, while walking back towards the tube, an almighty crash.. Down went a body. The screw had worked itself lose, and I'd not noticed.. Luckily the cost of repairs to the camera was around £200 and the lens escaped injury.. but now am wary of using it again, at least not until I've added some threadlock or something into it..