Cometdocs
Online tool for converting PDF files to Word, Excel, PPT, etc. It does a good job of making text editable, but converts SmartArt as static graphics. It would work for small text edits in a presentation where you don't have the original PPT file, but if you had a lot of SmartArt to rebuild it wouldn't save much time. It might work better for Excel spreadsheets than the PPT I tested.