Lulu Sofware's Soda PDF for Mac OS X isn't the most powerful PDF editing software around, but it has a decent fizz and it's free (although you can purchase additional modules for added features).
The utility lets you open, view and print any PDF file. You can also read any PDF file in 3D, read digital comic book files in 3D (.cbr and .cbz), fill and save forms, and create PDFs from Word, Excel and 300-plus formats. Soda PDF 7 makes it easy to create PDFs directly from scanners or even image files. You can even create PDF files directly from your scanner.
The easy-to-use tool lets you view any PDF file in Single Page Mode when you want to bring your focus to specific area of a document or in Continuous Page Mode to give your orbs an easy flow while reading your PDF document. You can even toggle to Full Screen when you want to block out the tool bar to just concentrate on the document.
Soda PDF offers a PDF experience equipped with Lulu's 3D Document View technology that allows you to flip through the pages of any PDF, CBR and CBZ file on screen like you would with a real book.
You can review, highlight text and add comments to documents. Soda PDF allows you to use keywords to find text with its Smart Search feature.
With Soda PDF's cloud and virtual drive integration, you can share, save and open your PDFs from the cloud and work on them with your browser of choice. You can also backup your documents on your Soda PDF Online Account storage for easy access.
If you're perfectly happy with Mac OS X's Preview, you may not need Soda PDF. And if you want more features, you can get more bang for your buck with SmileOnMyMac's PDFpen Pro or Adobe Acrobat than purchasing additional modules. However, if Preview lacks features you need, give Soda PDF a look.