Interesting question. Not long ago, I was also looking for a good PDF converter and editor. I tried the solution suggested in the post about the PDF to PPTX converter https://www.reddit.com/r/studytips/comments/1kpeq92/spent_hours_looking_for_a_decent_pdf_to_pptx/ and to be honest, I was very pleased. This tool offers a wide range of editing features and also supports many formats for conversion. It might be a good fit for someone else as well.