Canon 20d notes

The camera feels essentially identical to the 10d, but a little lighter.
Yes, it's louder and slightly smaller. Sounds about as loud as my 1D IIs I think, but the mirror slap in the 20d is somehow less jarring.

So far I actually like the color rendition better than the 1D II. I have never been 100% satisfied with 1D II colors. I really like the look of the 20d files.

It's also a relief to have a lighter camera with reasonably high resolution. Anyone who has carried a 1 series camera with a heavy L lens on it all day should know what I mean.
Automatic AF point selection actually works now, and FAST. I almost never used it on the 10d because it was so slow to determine which AF point to use. The 20d decides pronto, even in relative darkness! This is now a useful feature.

RAW speed
Apparently you can shoot around 27 RAW frames in 30 seconds, as long as you do not keep your finger squeezed down on the release the whole time. During a fashion shoot a couple weeks ago, while shooting RAW+JPEG very fast, I never had to wait for the camera. That's a first! The fast write speed in this camera really makes a huge difference.
However, if you do insist on using the 5fps mode for RAW, after the first 6 frames, the rate drops to around 1 FPS for quite a few additional frames (maybe 20 more??)
You can see the dpreview data here:
http://www.dpreview.com/articles/canoneos20d/page6.asp

FOCUS
The 20d focusing is really fast and seems very accurate. It's not noticeably slower to focus than my 1D IIs are. It does seem to be quite a bit faster to lock focus than the 10d is, and it's a lot more accurate.
Also, the viewfinder looks really nice and sharp to me. Easier to see what is and what is not in focus. Easier to manually focus than the 1D2 IMO. It has more "snap."

HIGHLIGHTS/BLOWOUTS
Been shooting mostly in RAW + JPEG. Dynamic range does seem to be better than that of the 10d. Importantly, the TRANSITIONS between areas with tone and those that reach 255 are very smooth like the 1D II and 1Ds, not a rough cut-off like on the 10d. This is a VERY important improvement in my opinion. This in combination with better and more consistent metering add up to a LOT more keepers than I even dreamed of with the 10d.
To my eye, the highlights are just about as good looking and as smooth as those from the 1D II.

EXPOSURE COMPENSATION
After finally shooting in direct sunlight with evaluative metering, it does seem that it is best to dial in -1/2 or -2/3 to keep the 20d from blowing some highlights. I found the same to be true with the 1D II and 10d.

NOISE
Noise seems to be more visible than on the 1D II at the same ISOs. I have seen traces of banding in the shadows on occasion. This is where the 1D2 is clearly better in my opinion. The 1D2 seems to have the cleanest shadows I've ever seen. The 1D2 files can be lightened quite a lot and remain clean while the 20d shows noise patterns a lot more quickly. Still, the 20d looks pretty good and I am confident that the noise patterns will not be an issue, especially in prints.

AWB
Sadly, the auto white balance still can’t do shit with most tungsten light…
How hard can this be to fix?? The Fuji S2 had decent tungsten AWB years ago!

WORKING TETHERED
Working tethered to a USB II enabled Windows machine is really fast. As fast as with my 1D IIs attached to dual processor G5s with the firewire connectiion. With the 20d, JPEGs seem to transfer in around .5 seconds and RAW files take around 1.5 seconds. Finally a workable tethered solution.

So far I definitely feel confident that it can replace one of my 1D IIs without any issues.

*Here is another interesting review by a working pro who owns a 1D II:

http://www.fredmiranda.com/forum/topic/131641

And now, some images (from the 20d and the 1D2):