Is it worth it to wait for the 2009 Kaplan Books?

I'm planning to write the GMAT some time at the end of the summer. I was about to buy a 2008 Kaplan prep book but noticed that the 2009 editions are due out on July 1st: http://www.chapters.indigo.ca/books/Kaplan-Gmat-Premier-Program-cd-Kaplan/9781419552045-item.html Will it make any difference if I...