I think the difference is in how the PDF documents are downloaded onto your system after purchase. After purchasing the 3.2 docs for Windows a couple of weeks ago, I completed the transaction by downloading a Windows application which downloaded the documents for me. The application hides the PDF transfer process and implements security features of some sort (for instance, it won't let you download the docs more than 5 times for example.) Since the app won't run on a UNIX box, I am guessing ComponentSource supplies its own download tool.
In short, the document is the same for all OS's although the download tool is not.
Thank you so much.