The developer of Synchronize! X Plus, Qdea, was one of the first to create a synchronization tool for Macs back in the early 1990's so if it's experience you're after, you can't go far wrong.
Synchronize! X Plus is a personal file synchronization and backup utility designed specifically for Macs. It takes advantage of 'pre-emptive multitasking', the full capabilities of the OS X file system, including 255-character Unicode file names and OS X file permissions. What's most impressive is the speed of synchronization with Synchronize X Plus! because files are copied at the maximum speed possible in OS X.
The app works via a very small and lightweight interface, which displays simply the target and destination folder. Browse to the targets you want them both to represent and select either Backup or Synchronization, then click the action button and you're done. You can configure from a selection of sounds to inform you when the transfer or backup is done.
The simplicity and speed of Synchronize! X Plus are its strong points. However, it can only handle one folder at a time, which could make syncing a bit painstaking unless you only want to backup one folder. An additional concern is that of privacy. Synchronize! X Plus requires you to submit a license number and computer ID over the internet to register and identify it. Although this is not designed to track you, some people may have be concerned about the privacy implications of this.
If you're looking for a simple and fast backup or sync tool for Macs, Synchronize! X Plus is an excellent choice.
