The Cosmos 1000 is queiter, made of steel, and has a better HDD cage, but it's hotter, and uses a door, so that can be a disadvantage to you. The Cosmos S 1100 is louder, because it is designed with airholes, to keep it cool, and made of alluminum. Its HDD cage is just an averge HDD like normal cases. The reason for the release of the Cosmos S was to fix the flaws of the original.