I work with I guy who owns a 5D. Now, I could be wrong... But he cares more about the cost of his camera, and the mega pix number. "12 megapixal, and cost me $7,000!!" then what the camera can do.
I said, "Wow nice camera. One of the few full frame sensors. How is the hi ISO performance?"
He mumbled something about the flash.
I said, "What's your shortest lens?" (I'm thinking wide vistas and mountains...)
He said, "I just have this zoom".
I could see in his eyes, his brain pondering the word "shortest".
........
Really, my little story has little to do with the topic at hand. I just had to tell someone.
Lots of things (cameras included) get bought not for what they can do, but for what people imagine they can do. My co-worker is a case in point. He has no idea what his full frame 5D is good for. But he is convinced his photos will be the best money can buy.
As for IQ of 5D vs K20D, I will be waiting to see the reviews. I am expecting great things from this new sensor. My gut tells me it will be the sensor everyone compaires to.
Did I mention I have the better office?