I'd wait to see some real-world results, first. I also don't really view it as an upgrade - more of a different lens with different (although somewhat overlapping) uses.
Thanks - I dont rush in to an early purchase. However I do like to have a long term plan, the 1Ds3 was a tactical purchase to carry me over until the 1DX or other ff come on stream at a sensible street price.
I have the 70-200II which I use a lot for portraits, the 24-70 would fit in nicely. I am not concerned about changing lens as I would have two bodies with me. This week I have had the 1Ds3 with 70-200II and the 1D4 with 17-40 for the wide angle, low light shots.
However I am finding the 70-200 just too long and am shooting at 70mm for everything except the head and shoulder (indoors). I even took some through the open doorway from the next room

. Ideally I would be taking at about 50ish, but as I take a lot of candids the zoom would match better
Here is one from yesterday, flashed to emulate light from a window and slightly desaturated to give a more period look. Model posed in the typical Victorian sombre fashion.
Camera Model: Canon EOS-1Ds Mark III
Image Date: 2012-02-08 12:47:54 (no TZ)
Focal Length: 70.0mm
Aperture: f/4.0
Exposure Time: 0.0080 s (1/125)
ISO equiv: 100
Flash Fired: Yes (enforced)
