I have had this lens for about a year, and although I initially found it hard to use, I am really glad I stuck with it. You get a lot of zoom for the money, and you also get a great optical performance - as long as you can hold the lens still. As others have already noted, it is heavy and use of firm support is essential. I find a beanbag on a solid wall or branch more useful than a tripod. As long as the lens is well-supported it produces fantastic results, far better than the 500mm mirror lens I had previously. If you want better results up the top end of the zoom range be prepared to pay a lot more for it.