This is a brilliant book. The book speaks for itself. My words can't do it justice. I think everyone should read this book.
The only thing that bothers me about it is that it needs updating. The author of this new edition did explain in the forward that it was written over a decade ago, in anticipation of the SSC, whose funding got cut. However, that is not enough. If the author or publisher did not want to update the text of the book itself, they should have provided footnotes throughout. For example, when it mentions that the top quark has not been discovered, that deserves a comment about its discovery, if not an appendix. It wouldn't take that much effort to just add footnotes, and it would help make the book more timeless.
Also, the paper in this edition could be better. The quality is not quite as bad as "mass market paperback", but almost.
Regardless of my few negative comments, this is one of the all-time best scientific books written for a popular audience.