It basically takes each page, turns it into an image, and compresses it. It's incredibly effective if your PDF is full of photos or scanned pages that are taking up way too much space.

Definitely. We set the default quality to 72%, which keeps text sharp and totally readable. Just don't drag the slider down to 20% unless you're okay with things looking a little fuzzy.

Yep! But since it's running on your computer and not a massive server farm, really huge files with dozens of pages might take a little while to process. Just give it a minute.