I agree that it is a nice tool for searching PDF files, unlike any other that I have seen, although it takes a few minutes to launch (true, I have more than 14,000 PDF files on my Mac). Results are really good. It takes time to index all the PDFs (once again, 14,000...), but once it is done, it works. It also adds new PDFs. And the developer is friendly and helpful, as I could see when I asked for advice when I started using the application.
But there is one caveat. After installing PDF Search, I noticed that cloning my Mac would take much more time than usual - three times longer, actually, up to 18 hours with a Firewire connection. First, it didn't come to my mind that it could have something to do with that little application, that isn't huge at all (4.3 Mo).
Then, as I monitored with Carbon Copy Cloner which files made a clone of my Mac take an endless time, I noticed that it was due to PDF Search files in the Library/Containers (com.mozkan files). It would take hours to clone them. I am not technically gifted enough to understand all that, but it appears that the application is creating for indexing purposes a huge number of very small files, ending with .dat: I spotted many of them in a folder named "words".
They don't take much space on one's Mac, and thus are not really a problem from that angle. But when copying all files on one's Mac, they make it an endless process. Despite liking the app, I decided to remove it from my Mac Pro. And after moving the app-related files to the basket, and starting to delete them, I realized that there were... more than 2 million files associated with that small application! Now I understand why cloning had become endless.
For those people who do not clone their Mac (but they should!), it won't be an issue. For people like me, the application cannot be used for that reason for the time being. Let's hope that the developer will find another way for indexing and finding PDF content.