Whether it is worth or not, it depends on how you define worth.
I used to buy the hype cycle out of recommended books by "the internet" (reddit, HN, blogs, etc), for example: the tipping point, wisdom of the crowd, paradox of less, this book, get things done, etc.
But then I figured out that I want to (and should) do my own thing, not to follow someone else's lead.
I sold mine last month and am now trying to get rid the other books as well.
Keep in mind that while it is 6 years old, most of the content are "concepts" of various topics from startups, competition, hackers/recruiting, etc.
I browsed found interesting information. For example: SE in UNIX/C Env book mentioned Unit, System, Integration, and Acceptance Testing. Just like those Agilist/Scrum books are doing these days.
Og Mandino book is sort of self-help book that seems a combination of a few recent self-help books.
They're both thin and easy to read. I suppose I would believe reviews about old books than newer books from now on.
[EDIT: reading that book brought me here. Never regretted that]