Here is what drove the move to D700. Indoor available light action shots. I got brave and let it go to ISO 6400... The D700 AF is FAST, it is a dream to use for this. I did about 10,000 swim meet shots with the D300 this past season, and have worn out my computer post processing the ones people ordered. It just isn't quite there when the light sucks. I limit the ISO to 1600 on the D300, it looks like I will be at least up to 3200 and maybe 6400 with the D700. 2 more stops is verrry useful when its gloomy.