So how do we come here? Well, the four-thirds member of the league is the 14-35mm f2.0 SWD, a lens that was delayed for a long time, was criticised by many. Most of the critiques related to zoom range, size and price. Well, looking at the Zeiss, or the Canon EF 24-70mm f/2.8 USM L or the Nikon AF-S Zoom- NIKKOR
Well, you can compare it to the Canon, selling at around $1200 at B&H. Why would you do so? Because Canon is the staple of photojournalists. Are there any other ways to compare? Surely there are. If you look at the nice little review from digitalcamerareview.com, you can see that the Zuiko makes compromises that are different from the Canon or the Zeiss. It insists on weather sealing and f2 brightness - I think the former is a must for a pro-grade lens, while the latter is a a) must for four-thirds because sensor size, b) unique selling point that has the power of differentiate on the market, c) nice touch many were waiting for. Along with this, is has almost zero CA, extremely nice bokeh, and remarkable sharpness, at the price of some vignetting. Well, what lens comes into your mind? Yes, a Leica, but a big, zoom version of that, which - in contrast to many Leicas - can bring together sharpness and fastness while keeping a superb bokeh.
I do not want to say it is better or worse than others. I do not want to say that Leica or Olympus is right to price its lenses the way it does. The point is only that if you see a lens which projects images in a way similar to the best lenses ever made (insert counter-argument here at will), you might find ways to rationalise size and cost that is larger than the competition in some dimension (especially considering field of view), but way smaller than the competition in other dimension (like bokeh and image quality in general).