First of all, I really like this lens. It is build like the proverbial tank and the 10mm range is out of this world, it's as wide as you can get at the moment.
Colour rendering is fine, but when the sun is in range you get some nasty flares.
Putting the lenscap on or off with or even without the hood on is a real pain. After almost losing this lenscap at a congress (it's a miracle I even found it back) I bought a genuine Nikon pinch-type cap which is simply wonderfull.
Don't even try to flash with your camera's internal flash unit, because the large diameter (77mm) will for sure cast a shadow.
I believe I got a reasonably good copy, because there are no soft spots, the image is consistent and color rendering is good.
But I cannot help to wonder why so many people rate this lens as "sharp". Because, actually it is not that sharp. Not even at F8. Don't get me wrong, it is acceptable enough and you won't see it on a 10x15cm print. But it's simply not sharp to the pixel (and I only got 6 millions of them). It cannot match e.g. my Nikkor 18-135mm/3.5-5.6 or my very old Nikkor 28-70/3.5-4.5.
Sure, I do enjoy it but I wished it was just a bit sharper. Other than that, it stays on my D100 for about 70% of the time. And if it's not on mine, it certainly is on my girlfriends D40!
Ultra wide angle is addictive... consider yourself warned!