It was essentially because I need a lens wider than 24mm, and the Tamron was the best-regarded of the readily available, non-expensive options. $250 shipped, with a $10 rebate is less than I paid for any of my DX lenses, by far, and less than it is selling for on most photo forums.
Why not the Nikon 17-35? Well aside from its' ridiculously inflated price recently, it isn't even the best ultrawide Nikon sells anymore. If I'm paying the premium for a high-end Nikkor, I'm going to make sure I get the best, the 14-24.
Anyway, here are a few shots I got at a local lake after work today. First two are with the Nikkor 28-105mm f/3.5-4.5, the latter with the Tamron.
Whether it is a weaker anti-aliasing filter, lower pixel density, or just plain better sensor technology, I am amazed at how much sharper the files (RAW) are coming out of the 700, compared to the 200. I am comparing shots using the same lens, and same RAW converter (ACR 5.4). Go figure.
There definitely are a lot of small nicities on the 700 that add up to a more pleasant photographic experience. Live view came in handy a few times near the ground. I definitely like having the built-in viewfinder shutter, and the multi-controller on the MB-D10 is a godsend.
Funny though, that the change I am having the hardest time getting used to is the CF card slot, I keep looking for the release slider from the 200!