No, I am not going to ask what is the difference in this and the Certification Exam Guide.

What I want to know is what is the difference between the 2nd and 3rd editions. They both cover the 640-901 exam and have the same authors, but there is about a $40 difference in the price and the 3rd edition is 2007 while the 2nd is 2005. I am just wondering if it is worth the extra money to get the latest edition as this is a supplement for me and will be used to iron out the details.
Thanks,
Cy