Having had Nikon equipment since the 70's, I have just upgraded from the D300 to the D700, and bought the 24-70 too...All I can say is, it is without doubt, the best lens I have ever owned. I just love it. Its heavy, but I like that, it feels what it is, an expensive, classy lens.
I've only had it a week, but already the images taken are just so tack sharp. If you can buy it..do so !!