You can't appreciate the value of good editing until you get to see what was cut. The "trilogy" holds together because this material was removed. Reading this book changes how the three other books feel.
For example, Frank (Lisa's father) 's role as a foil for Jed to dismiss is muddied when you now hear Jed discuss Frank's beliefs in more detail. Frank was an LSD advocate, and Jed agrees that LSD is useful as a tool to reach human adulthood, if not possibly enlightenment itself. However, Jed is indifferent to weather a culture that embraces this tool would be a good thing. (Remember, there is no longer a distinction between good and bad from his non-dual perspective.)
Similarly, his discussion of witnessing as a discipline undercuts his rejection of techniques other than spiritual autolysis as mainly ways to pass the time in the dream state, when you have no intention of leaving it. At the same time, it allows you to see more clearly how he was able (and in theory, you might too) to stop identifying with his dream state character.
Probably the best part of the notebook is the ending in which he describes his own awakening.