The site found that the iTunes download looked surprisingly good when compared to Blu-ray. It did will with color reproduction and text; however, it was slightly worse with movement and highlights.
I was surprised to see how close the iTunes 1080p download comes to Blu-ray, considering that it's only a fraction of the file size. And let's be honest: there are lots of Blu-ray titles that look much worse than this iTunes download. But despite an impressive effort by Apple, Blu-ray still reigns king when it comes to image quality. And unlike iTunes titles, BRDs can have uncompressed multi-channel audio, multiple audio language options, and special features. Am I being greedy in wanting both good-looking downloads for convenience, as well as buy-once-play-anywhere Blu-ray discs of my all-time favorite movies?
A couple comparison shots can be seen below. Hit the link for more. Note: iTunes is always the top or left image.