I love this lens, not as wide or as long or as fast as others maybe, but I often cannot bring more than one body or change lenses in the field and this one does it all. As others have said built solidly, I love the push-pull, once you are used to it you can manipulate it quickly, the IS is a big help. It is variable aperture. And it's really not that big once you are used to it. Cannot use canon teleconverters.