My employer relies on her calendar VERY heavily. Since this program is registered per user, not per computer, I am able to update her calendar from my computer as necessary, in addition to her automatic sync. She switched from a Palm to the iPhone and somehow her calendar was corrupted in the process. When the
Apple store was unable to help, this program saved her calendar!

It's very easy to use. The only con I would say is that it takes a long time for the initial sync. The updates don't take as long and we haven't had any trouble as far as the updates interfering with anything.