I didn't play with it long, but our Nikon rep was in with this very lens today
Considering it's his job to sell as much high-end product as possible, he's always been extremely honest with me. He said that since it's a variable aperture lens, it's not going to be as good wide open. But stopped down to f/8, it's as good as the 16-35 or the older 17-35, but still not as good as the 14-24. In his words, hikers and other people that shoot mostly during the day will be able to take photos that are just as nice as more expensive lenses, and it costs and weighs less. But if you're doing weddings or something in lower light, you're definitely going to see the difference between the 18-35 and the more expensive lenses.
I only had time to take a few photos indoors and outdoors before I had to let my coworkers handle it, but that seemed pretty accurate.
I hate to give 'my rep said so' as any sort of rationale; but there are a couple guys I work with that are really honest about the product they sell, and in their case I do tend to take their word.