They tend to use slightly different strategies, so yeah, I would say it adds something because it will give you a different perspective. I have the PR book and the strategies are very helpful, so if you're looking for some more help I would recommend it. PR's pretty well-known for having the best GMAT verbal prep.
Yes, they do take a different approach - esp. for Reading. I found it a little interesting, but I am not sure how possible it will be.
In any case, if you can swing by the Barnes and Noble or Amazon.com it is not much. let me know what you think about the book.