Randy,

Note that the 1D-IV is a crop camera, with a 1.3 crop factor. Of current Canon bodies, the 5D and 1Ds are full frame, as is the coming 1Dx.

What is your own experience between the D3x and D300s? My wife and I used to shoot Nikon and shared a D300 and D700. There was never a clearly better body. The pixels on subject of the D300 were preferable sometimes, the beauty of the D700 pixels were preferable other times. We now shoot Canon with 1D-IV and 7D bodies. We both tend to use the 1D-IV more than the 7D, as much for other body factors as the better IQ.

Alan