Hi, just thought I'd chime in that the book and DVD are fantastic, and that what they teach is invaluable!
I know what allthumbs means about it not being scale-based, but it's all the same building blocks, so I believe that any shredders wanting to be able to play the changes or jump around keys or have more satisfying melodic moments would also benefit, IMHO. Seriously, if you want to shred, you'll be a better and more melodic shredder for having learned
PlaneTalk, just as any blues or jazz or flamenco or whatever style of player would also benefit immensely.
James