Free to Focus

I was curious to read this book to know a little a bit more about focus. I already use GTD as my productivity system and it's clear that some sections are a GTD derivative with a different name.
I was a little bit annoyed that I had to go to the author's website to take the initial assessment, leave my e-mail and then I started receiving all these promotional e-mails to buy his planner. That threw me off a little bit.
But the message in the book is not unlike any other good productivity system: eliminate non essentials, group similar tasks for efficiency, eliminate distractions and use time blocking to focus.