Peter Gutmann himself wrote the following:
If you're using a drive which uses encoding technology X, you only need to perform the passes specific to X, and you never need to perform all 35 passes. For any modern PRML/EPRML drive, a few passes of random scrubbing is the best you can do. As the paper says, "A good scrubbing with random data will do about as well as can be expected". This was true in 1996, and is still true now.
It seems like the method of data reconstruction described in the paper is more of an academic problem than something that is done in real life.
Nonetheless many data erasure tools are implementing the Gutmann method. (For example DBAN, Recuva, shred, TrueCrypt) Is there any real life scenario where the Gutmann method is actually needed? Or do they just provide it as a feel-good feature for paranoid users?