I am a proud and very happy owner of both Olympus E-520 and E-1. I shoot only RAW and convert and PP with Adobe Camera Raw and Photoshop Elements 6.
I can see difference in the image quality, dynamic range and colors between the cameras. The older one, E-1, produces images which I tend to prefer. The colors seem to be better and more warm and "lifelike", the dynamic range is also better, and if you look more carefully at darkened areas there is less noise in them.
I wonder what's others opinion?
I love my E-1. It's a rugged tool. I am thinking of having another body with Kodak sensor inside and a higher resolution, before they will disappear from the second hand market. Which one should it be? (E-300, E-500 or E-400).
I am also interested in how the E-1 and E-3 stack up - I have owned the E-510 and the E-3 is better in terms of noise and DR. I would be interested to see whether any owners of both the E-1 and E-3 would recommend the E-1 as a useful complement.