Synchronization on the Mac is an absolute breeze compared to trying to do the same thing on Windows. TimeMachine is a perfect case in point although not everyone wants to devote an external hard drive (or part of) to backups.
There are always ways to make syncing easier or cut out the need for Time Machine and SyncDifferent attempts to do so in the most streamlined way possible. It's not a sophisticated Sync tool by any means but if you're just looking to sync one particular folder constantly with another device (such as a constantly updated work folder or downloads folder) it's ideal - especially for those new to syncing.
Synchronizing is easy - simply drag the folder of origin and destination to SyncDifferent and click the sync button - there's nothing more to it. You can create a list of files and folders in your favorites that you constantly synchronize. Of course, the developers can make no guarantees that your data will not be damaged in the synchronization process but then again, no one does so it shouldn't get marked down for this.
SynchDifferent isn't really different - it's just an ultra easy way to sync and backup a folder or series of folders on your Mac.