I love learning languages, and have read the book of several polyglots, which I enjoy usually to a great degree. I was interested what Benny has to say about the topic, as I have learned 5 foreign languages in my life so far, and speak fluently three of these.
I really loved the book. Mainly I've read it to have fun, and follow the adventures and experiences of Benny (check out his blog if you haven't done so), but I've also got some great tips from him. What I found great about it is that he writes from an "upper level perspective" - strategies that work for any language, and he gives a birds-eye overview of different languages, and what general approach works for them. I have to note I didn't read the book cover to cover in one go, but read chapters that sounded interesting to me, until I finished the whole book.
He tackles also some topics, like the myth that children have an advantage vs. adults in language learning (which I also think is a myth, now I learn languages way much faster compared when I was a child, any age), what to learn at the beginning, and what to learn later, and how to make use of a limited knowledge set to get the message across. I discovered that I already use many of his tips, but I was doing them unintentionally.
There's one thing that perhaps readers need to keep in mind: different personality types have different preferred learning modes. There are many models about this, my favourite is the LSI Kolbe Learning Type Inventory (see wikipedia or google it). It sounds to me that Benny has an "Accommodating" style, one that communicates a lot, lives in connections, and learns a lot through trying out, personal experience. However, I've read from other polyglots who had different profiles, for example Kato Lomb, who was more an observing style. Instead of communicating right away, she read books from a new language, and over time she figured out patterns from the books. My guess is that if you have a similar learning style like Benny, you will feel comfortable/easy using his tips, if you have a different learning style, you will feel less comfortable, but you get some new ways to try out.