I'm in the process of getting another certification. One particular review guide was highly recommended, so I looked on Amazon to see how much it cost.
I immediately noticed that the title was available as a
Kindle Edition for about $4 less than
paper. Given the convenience of the Kindle, I decided to go with the Kindle Edition.
As soon as I bought it I opened it to the index, and paged through it. The ebook has all the sections of the paper book including a description of what was included on the CD. I didn't expect to get the CD, of course. But I thought it was rather funny that the CD contained not just practice tests. It also held a PDF copy of the review guide.
This is for publishers to ask themselves: What is the point of buying a Kindle Edition when I can get paper+PDF for $4 more?