Is the Gutmann method the best method?
No. Most of the passes in the Gutmann wipe are designed to flip the bits in MFM/RLL encoded disks, which is an encoding that modern hard disks do not use. In a followup to his paper, Gutmann said that it is unnecessary to run those passes because you cannot be reasonably certain about how a modern hard disk stores data on the platter. If the encoding is unknown, then writing random patterns is your best strategy.
