I liked some parts of the book. I liked the idea of mixing leisure and work, rather than putting off life until retirement. The idea that a business doens't have to keep growing. At some stage once the business is providing an adequate income, then a decision can be made to make it easy to run, rather than getting a lot more difficult customers, to get a bit more money.
However, there were a number of things I didn't like about the book. Ferriss's business was some kind of supplement for either althletic performance or better study skils. In fact he switched between them with out change, as far as I can tell. So my best guess is that his product is a placebo. When he was at University, if he got bad grades, he would go to the TA and ask them about his grades for a couple of hours, until he wore them down. Then the TA would be too scared to give bad grades again. So he is a wheeler and dealer type of guy.
Also he recommends not reading much. Look Tim dude, what did they fu*cking teach you at Havard. I like reading.