Sometimes they are complimentary other times exclusive. The drivers are the key. I could write drivers to allow my Apple CD Drive to be attached to the DOS machines. I regulary copy files from so called DOS CDs onto my Mac harddisk and write little translators for the resulting files. If one has Mac software that is generic enough, thses files can then be concorded or searched or manipulated in any required manner.
Files are files.
I short, the Mac is much easier to work with, but most CDs assume that the users have DOS machines. Both are useful. Be sure to read more of the OmniPage review to get a better idea of the product.