10 out of 10 points and recommendedAccurate AF, excellent tracking, sharp wide open, nano goodness, bokehIt's not 1.2 ? ;-)
This is an excellent lens period. The changes are subtle compared to the D version, but add them up and it's a different lens. I sold the D version to buy this, so the purchase price was heavily subsidized by the old lens.reviewed January 5th, 2011 (purchased for $1,590)
I don't understand why others are comparing it to Canon's 1.2 (where at 1.4 it's technically stopped down a bit), or Nikon's 1.8D (that doesn't go to 1.4), or to Nikon's 70-200 II (that is meant for sprorts and sucks at less than 2.8), or to other brands that are similarly priced as this lens is but lack autofocus. This is a different lens than any of them and is used differently than any of them. And if you don't think the price is fair, then you don't really need this lens. The 1.8D will suit your needs just fine. Just saying.
The AF speed going from extremes isn't as fast as the D, BUT if your shooting style doesn't require this, then the AF will be plenty fast for you. I think with the new 1.4 G lenses, Nikon struck a better balance in AF speed and accuracy vs say the 70-200 II (not that the 70-200 isn't accurate, very much so, but there is a bit more room for focus error using 2.8 lenses vs 1.4 - at similar focal lengths).
The D is suited more for portrait work, where as the G is a better all rounder 1.4. The G is sharper at infinity at 1.4 than the D is.
The G renders the image warmer than the D. Which I find better since it matches the look of my other G lenses. Makes batch editing easier/faster.
The build is tank like. It's not the same as the D of course, but it's not an 18-55 either. It's heavy, for it's size. There is a lot of glass in there. It feels like the 24 1.4, maybe a tick lighter. No complaints. It's not the metal of old, but feels solid.
The difference is like the change from the 70-200 I to 70-200 II. Subtle in many places, and subtle in improved image quality. John and Jane Doe may not see the difference, but if you're reading this, you are the type that will see and feel the difference.
Lastly, it's quiet. Think AF during video. Even with external mic. The G is quiet.