Richardson book (H.264 and MPEG-4 Video Compression) is the best book on h.264 -- by virtue of being the only one.
The cover of Symes' book proclaims "Featuring: JVT/H.264/MPEG-4 Part 10". However, there's one chapter on JVT, and it is somewhat sketchy. The only level of real detail is on the transform. The rest of the AVC/h.264 standard receives brief and superficial coverage. The coverage of WMV-9, an analogous next gen codec, is even sketchier. It doesn't mention the SMPTE VC-9 standardization effort, based on WMV-9.
Next gen codecs aside, it's not a bad book as a general overview of compression. It has a breezy style that's easy to read. While some sections are quite thorough, it doesn't consistently dig past the surface.
Here's an example:
"Context-based adaptive binary arithmetic coding (CABAC) is a development of arithmetic coding mentioned in Chapter 3."
-- page 243, Chapter 12, JVT
"Explanation of the arithmetic coding process is beyond the scope of this book."
-- page 47, Chapter 3, Entropy Coding
In a nut shell, this book is a good addition to the video processing bookshelf, but it won't stand as a definitive reference to this new protocol. Maybe next edition.