Every slide becomes a page: its title, then its bullets. This is the TEXT of the deck, not its picture, and it is the most visible difference of the three tools.
What it does not do: A slide deck is a visual object: images, shapes, colours and positions are not carried over, and what comes out is its text. The order of the text boxes is the file's order, which is the order they were placed in, not necessarily the order they are read in. What this tool does not do, and it is the main thing: reproduce the original layout. It reads the CONTENT of the file and lays it out again with our typography, on A4. Margins, fonts, sizes, colours, columns, headers and footers are not carried over, and page breaks fall elsewhere. Images and charts are not carried over either, and the screen counts what is missing before you save. Finally, our font writes Western Europe: a document in Greek, Russian or Chinese would come out empty, and the screen says so.
Nothing is uploaded. Cut your network connection once this page has loaded: the tool keeps working. How to check it yourself.