I have both.
IMHO you don't really need the book, as the software has all you need, unless you want the DJ story. If so, then you need the book. I have used the book to journal details about the blocks as I have made them.
As RoseMarie mentioned, you can change the size of your blocks, bigger/smaller as you wish. Also, you can change the shape to make rectangles. Kind of a neat feature, if you want to do something away from the traditional DJ. I see it as something I will use later for other projects.
At first, the software appears to be not the most user friendly, but now that I have used it some, I'm OK with it. There are many options for printing each block ... line drawings, templates, paper piecing patterns, and rotary instructions (where applicable) for each block.
I highly recommend you getting the plastic templates. I hesitated in purchasing them, but have found them to be a very valuable tool to square up and trim the blocks.
I now have 82 blocks finished!