In all honesty and to avoid future confusion, I would not suggest purchasing any of them. I much prefer the DSI's books (the green "reference" book and the red "technique" book).
If you are looking to the Traditional Chinese Medicine (TCM) approach to vital point usage, then I suggest the DSI books over George's. I own all of George's and have been to training with him and several of his higher ranking yudansha. I prefer the TCM paradigm as to what George and most of the DKI teaches.
You have have a look at the DSI products by visiting their website at: http://www.dragonsociety.com
DISCLAIMER: I am not a member of this organization, although I did co-author the first book (writing the chapeter on the wuxing/gogyo).
Hope that is of some help to you!