Interesting that no one, other than people paid by Canon, yet seems to have said wow this camera is amazing: everyone seems to be underwhelmed unless I am interpreting comments wrongly. Battery life sounds a potential problem which will surely be worse in very cold weather, 20D batteries used to die on me below -3C: even the amazing (in his words) A R---e only used it up to 1600 ISO on tame deer and there still doesn't seem to be a real AF action test but did notice in Canon tips it says to turn off colour detection in AF as it noticeably slows down AF speed and acquisition so if that is the case it's not going to be a lot of use for flying birds?
I've been expressing doubts about the battery life, but other than that I'm happy with the camera.
Having said that I was out today and fired off another 100 shots on the camera on Manual, Av and Tv with Auto ISO for the Tv shots. Battery count is now 463 with 11% remaining, so it seems to be performing a bit better as the charge reduces, but that may be a by-product of treating it with kid gloves regarding replays etc.
I may turn out to be surprised by the time I need a charge. On current form I might finish with about 520 or even better - significantly more than the 350ish I was looking at when the charge was 50% - we'll see.
Regarding high ISO here is the goldcrest shot I posted a couple of weeks ago, taken at ISO 5000. (Tv, 1/1000 sec, F6.3, Auto ISO). The sun was out, but the bushes and trees overhead reduced the light considerably, hence the high ISO.
The first picture is as it came from the camera, unedited apart for resizing for the web
The second image is cropped and a bit of sharpening with no noise reduction.
The third image is the same as (2) but with Neat Image noise reduction applied selectively to bird (20% luminosity, 5% chrominance) and to background (50% in chrominance & luminosity). My old 7D wouldn't have done anything like that on ISO 5000.
The sanderlings (and purple sandpiper) were flying against surf in awful light, ISO 800, 1/1600, F 6.3 Manual (slight under-exposure). The autofocus found them.
All shots with the 400/F5.6 prime.
