I just finished installing the Oly viewer and I compared some EP3 photos switching directly between Oly/Aperture with the same pics at the same screen size. The oly raw files looked considerably better with the Oly viewer than with Aperture direct from the camera with no additional work. The Jpegs looked essentially the same on both programs. BUT one shot of some textured glass with the light shining through from behind showed dramatic moire on the oly viewer (both the raw and Jpeg images) while the same images on Aperture did not show it. I have no explanation - it's just an observation that I found odd.