One thing that I think is over looked all too often is where the images will end up. I am sure many professional photographers print large images, but there is a large group of hobbyists out there that only view them on computer screens or print 8x10 or smaller. So when everyone says "I can clearly see the differences at 100%", it is a moot point for many photographers who buy the gear. Professionals who do print large should very much care, but for a large portion of the people that only post online, that is definitely where the placebo effect comes in. They see those people who NEED the very best, and then zoom in to 100% to test sharpness, and then output the image to 1024x768 for web viewing.