I remember finding my first issue of 2600, in a bookshop attached to an enormous, secretive government laboratory. Those were in the days after ESS but before the Internet (well, we had NNTP and SMTP and telnet, but HTML hadn't been invented). It seemed so illicit and exciting, I bought every issue I could find for years, and even wrote one article for them.
Over time, I read it less and less, both because the writing was generally bad, and because the revelations were often so weak. The Best Of book fairly reflects the content of the magazine -- it gives a good sense for the passions of a particular technological subculture, but much of what is here is dross.
So many articles were clearly written by people who did not know much, and who punt when they get to difficult work. "The encryption is done by a custom chip and, uh, you might want to decompile the EEPROM and see what's in there." Or they contain only trivial information, made to fill many pages through the inclusion of anecdotes about how the writer came to know the trivial information. (Four pages on how you discovered that ATMs run OS/2? The entire article could have been reduced to four words: "Many ATMs run OS/2.") And then there are the political articles, most of which are screeds about how the government and/or big companies are coming to take your freedom away, and their desire to be paid for your pirated movies proves it.
In some cases, it is hard to imagine how a given article was selected for inclusion in the magazine, let alone for reprinting in the book. An essay on the mathematics of lotteries is particularly weak, using high school level combinatorics to argue that nobody should ever play. The article contradicts a much more interesting essay earlier in the book in which the weaknesses in certain lotteries were revealed and methods for exploiting these weaknesses detailed.
The best material in the book is historical -- the stories of individual hacks, arrests, court battles, etc., by the people involved. Emmanuel Goldstein could have printed just those and had a better book while saving 550 pages.