The Bilingual Edge probably would have gotten five stars from me in 2007 when it came out. Now, unfortunately, it is quite out-of-date. The research is old and this field has really come so far in the meantime, meaning that a lot of very important findings are missing, while what is present is no longer mainstream or cutting-edge. The cultural context is also very dated, meaning that a lot of suggestions are no longer helpful (e.g.: TiVo, buying a region-free DVD player). A lot has changed since 2007, and the book doesn't feel relevant like it would have at that time.
Similar to Eowyn Crisfield's "Bilingual Families", the book includes some questionnaires and templates family's can use. Crisfield's book is much more up-to-date and, in my opinion, its templates are better.
Putting aside all of the datedness, there is another major problem I sensed in The Bilingual Edge. The book focuses far too much on younger children, in my opinion. Almost all of the stories, including the authors' own, were about children under 10, usually under 6. The unfortunate reality is that many (if not most) bilingual journeys in the US and other monolingual societies falter as children pass these ages, and the authors seemed almost unaware of this, with almost all of their advice and attention devoted to the much easier younger ages. It made the book feel quite naive, honestly, or at times sugar-coating. I seriously wonder, having heard the authors' personal stories, if either of their children (Miranda + Graham) ended up actively bilingual now in 2022. Maybe I'm just being cynical.