Let me provide an answer in slightly more general terms - not specifically for the PPC tool. I
have tried the PPC tool, have learned from it and have used what I learned to rebuild several several small PPC sites. AND I have learned so much more by reading through existing threads that the overall experience has been well worth the investment. And an investment it is; because investing in one's education is always beneficial.
However, what I have learned
specifically in the three short weeks I have been "exclusive" has helped me to fine-tune the Google Adsense and SearchFeed/FindWhat PPC programs I have been using. My daily PPC earnings have more than doubled since I upgraded. I will have the investment repaid before the "Ides of March."
Can't ask for more than that, eh?
.