I did purchase it and that price is a STEAL. I'm thinking of doing a full review on the lens (written, the videos are too much work), but I'll give you a few thoughts now.
First, from 180-400 is remarkable - very prime like. However, the TC in mine isn't all that impressive. I've tested against just attaching a 1.4TC and my 14.TCIII is actually sharper than the built-in one on this lens. In fact, one reason I haven't written a review of it yet is that I want to send the lens back to Nikon and have them check it. I would think the internal TC would be better - or at least as good - as the 1.4TCIII, but that's (currently) not the case with my lens.
So, my advice at the moment is to only consider the lens if you intend to use it primarily in the 180-400 range. I know a lot of people buy the lens thinking it's more like a 180-560 when you get the TC involved, but in my opinion, I think you should only get the lens if you really do need to be in that 180-400 range on a regular basis. Oh, and that zoom has proved really useful at times - allowed me to get shots that were otherwise impossible (I was too close for 400mm, had to zoom down).
Now, when you are using it from 180-400, it's fantastic. Prime-like sharpness, fast AF, everything you would expect from a lens of this price. The lens is fully featured, weather resistant, and rugged. However, that also makes it very heavy to lug around. It's not the easiest lens to handhold, that's for sure.
Below are a few shots, all in the 180-400 range of the lens. These were part of my D6 review - there' more on the site (see the
review page for a short description of each shot - scroll down past the video and ISO tests).
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