I don't use the paid version, I only use the free version. The reason is to clean all the files/registry entries left when uninstalling graphics card driver.
It's one of the most famous tools used for this purpose. You will find more about on the best hardware forums (I think i can't talk about other forum names here).
Other famous tool to replace driver fusion is DDU.
PS: I uninstalled bitdefender, it's an horrible software... Bugged as sh**.
Any recomendation? I don't want qihoo since i don't trust chinese software xD