Blu-ray's been atop the home entertainment mountain, with only fleeting competition from HD-DVDs, ever since its introduction. Since then, home internet connections have gotten faster and the quality of downloadable content has improved such that iTunes can offer 1080p versions of your favorite movies. But, does iTunes really provide the crystal clear quality we're accustomed to seeing from its disc-based competition? The good folks at Ars Technica decided to find out using the film 30 Days of Night, and results were mixed: text and color reproduction were virtually indistinguishable, but the compressed iTunes version showed warts when dealing with bright spots and dark gradients. Highlights in the downloaded movie were a little blown out and lacked the detail of their Blu-ray counterparts, and banding was visible in the downloaded movie during a darker scene. So, it seems that supreme video quality still comes via optical drive, but if you're willing to sacrifice a smidge, the iTunes alternative is still pretty darn good. Don't take our word for it, though, there's lots of photos detailing the difference at the source below.