RW: I am in love with this lens. Can't wait to rent it again. Some things to consider: 1) it is HUGE (roughly the length of an orange traffic cone with the hood extended) and HEAVY (8+ lbs). 2) it is *incredibly* sharp, even wide open. I took it to the zoo this weekend and shot several animals in difficult lighting conditions. The lens made it effortless. When I got home I was amazed at the quality of the photos, and the virtual lack of post-processing needed in Lightroom. 3) If you plan on using this on a tripod (which you should - it's heavy!) make sure you have a gimbal mount for it. Technically you can get this lens onto a ball head, but you won't enjoy it. A gimbal mount will make your life much easier. 4) With a strap like a Black Rapid, you can easily carry this lens around all day (e.g. at the zoo), but you'll need a way the strap properly (e.g., a spare bostail). Don't connect your Black Rapid to your camera body with this lens mounted - it's too heavy.