Mark2Mark wrote in post #9848472
The price isn't really the issue, I was just (slightly) worried about people referring to this lens as "the dust pump" and that it has an older push-pull type zoom.
Is dust a problem?
Think you're taking it a little too literally. The 24-70L is called the Brick, doesn't mean I can use it to build a house or that it weighs as much (although a house of L lenses would be fun). There's only 2...ish lenses with the push-pull design but both are Ls and both are used by professionals. The 100-400 is a fantastic lens, was thinking of adding one to my collection (but then I bought a car and my 7D) but I'd still buy one now rather then later. The push-pull design is quite fast once you get used to it.
Depending on what you use it for, you could always check out the 400L prime, or a Sigma 150-500 (or 50-500 thats coming soonish). Both the sigma's are twist zooms (thats the right word I think).