I have just tried the pro version since my first post on this thread, and as mentioned earlier, the pro feature seems to work by recording every change done to the system, on the filesystem and in the registry. The trick is that if a background install occurs at the same time, uninstalling using the record of changes may yield to bad results. Recorded changes can be optionally unselected at uninstall time, but this requires a thorough manual examination, and may not work in every situation.
So, I'll probably stay with the free version for now.