Within reason, similar cameras perform the same, you could give a 16 mega pixel to a novice and a 1 mega pixel to a pro.
I know the above is an extreme, but after you get to so many pixels, anymore never really come into play unless you are printing out to A3 and above.
I think most of us fall into the 'gadget' trap at one time, but after a while you just tend to use what you have and enjoy getting better results each time. (even though I am looking for a new lens) LOL :laugh: :laugh:
I would suppose in reality the 5d has to be better value today, but when the 1ds came out it was cutting edge.
The 1ds is still a beast of a camera, and will out perform most other cameras in most areas.
The 5d will, I imagine, be similar to the 20d in handling, but has the full size sensor, so the lenses you use will produce images as you set them to, by which I mean there is no cropping factor to consider.
It looks like Canon have produced this camera to allow the masses to take advantage of full frame and high mega pixels, but this comes at the cost of weather sealing.