Okay, I had a look at the 250 patterns book again (the "old" book).
For 4, 8 and 16 strands the old book offers more patterns. New things I could find were core wrapping and color changes through thread exchange with the core. The braiding instructions are a bit more detailed in the new one.
What is completely new in the new book are about 30 or so 24 strand braids, some involving core-mantle substitutions to increase the number of available pattern sequences. For an example see the front cover of the book.
If you want to get into braids with core and more complex braids, I'd recommend buying the book. Otherwise the old book is more than capable of keeping you busy