Each edition does have some degree of unique specialization outside the core functionality. Simple Sync for OS X for instance will control the OS X system that it is on. That obviously does not apply to other editions. Simple Sync OS X also has some local backup/restore functionality that does not apply to others.
Beyond that, all of the functionality is generally the same. Regardless of system of course, you need to make sure it never goes to sleep and that Simple Sync is always running. In the case of Android and OS X, we make sure it runs in the background. For Simple Hub, you don't need to worry about any of that of course.
I think the calculation usually goes something like a dedicated Mac Mini is $499, a dedicated (of very good quality that can run 24/7 powered) Android device can cost a fair amount especially once you venture into the small subset that have built-in Ethernet and a recent OS version, but is usually less than the cheapest Mac Mini, and then a Simple Hub is a dedicated Android device with Ethernet designed for this purpose with automatic update of Simple Sync.
Thank you.