DMG files are rather difficult to work with, since they don't work with Windows by default.
Meanwhile, iAtkos is distributed as a 'DMG' file, which is a proprietary 'disk image' format made by Apple.
iAtkos only works with the less common (and more expensive) dual-layer DVDs and Bluray discs, because the iAtkos installer is slightly too large to fit on a regular DVDs. However, there are a few reasons why you may want to use Niresh instead. iAtkos is the far more popular choice of the two. If you're interested in installing Mac OS X on your PC with a distro, then you'll have two main options: Niresh, and iAtkos ML2. If you don't have any qualms with the legal issues regarding distros, they're actually the most convenient way to set up a Hackintosh. Distros are pirated copies of Mac OS X that have been modified to work with a PC.