While I, personally, find the structure / length completely appropriate I do agree with:
1) The printing is terrible, dark-blue print with an ugly typeface on a mock graph paper background. And the faux "handwritten" side notes are actually as hard to read as somebody's handwriting. Typography is actually supposed to make something *easier* to read, not harder.
The mock graph paper and the right-justified typewriter font make reading the main text a pain. Everybody in the office whose read PDTN has agreed. Pity since the content's nice, and O'Reilly books are normally a model of clarity.
If you're new to Perl testing I'd definitely spend the extra effort to get past the presentation.