ORPALIS PDF Reducer Free is a tool which can take a PDF file and resample its images, omit unused objects and more, so reducing the file size while leaving it looking more or less the same.
To try this out you must first specify a source file and a destination folder, before clicking the "Start Batch" button. (Despite the name, you can only shrink one file at a time in the free version.) The compression process is slow, so you'll need some patience, but a status display does at least keep you up-to-date with the pages converted so far.
Is it worth it? Not always. We pointed the program at a huge file where each page was a scanned image. Processing this took 50 minutes, and the end result was no compression at all. We weren't impressed.
We also discovered an annoying issue. If your document's destination folder is the same as the source, ORPALIS PDF Reducer won't warn you of this, but it won't overwrite the original file, either. Instead it processes the entire file - no matter how long it takes - before displaying a message telling you that the program achieved no compression at all. The "can't overwrite" error is hidden behind a tab, and even if you spot that, you'll still need to run the entire compression process again.
Once you understand this, though, it's not such an issue. And we discovered that many files could be cut by anything up to 80%. That level of reduction did involve significant quality loss, but the settings allow you to control this. You can set your preferred image quality and resolution, opt to remove various content (bookmarks, annotations, form fields, embedded files), discard unused objects, and more.