SyncTogether doesn't come without its disadvantages. First, if you own more than three Macs you want to sync, you'll need to purchase a second $50 license to cover those other machines. Also, SyncTogether uses a direct connection between Macs (even when you're out and about) to do the actual syncing, which is a double-edged sword: on one hand, the security nuts in the audience will likely have peace of mind knowing that their data isn't lying around on anyone's servers, but this also means that setting up SyncTogether isn't quite as "it just works" as Apple's .Mac. Lastly, and this is a major gripe many users have against Mark/Space's practices: SyncTogether doesn't have a demo. The company seems fond of forcing customers into paying up front to get their hands on the software, so all we can tell you is purchase at your own risk. Any readers care to share experiences in the comments?
At the end of the day, this .Mac customer is definitely interested in what SyncTogether has to offer, especially since I'm only on board these days for app syncing and the iDisk. Still, I think I'm going to have to wait until comments roll in from those more adventurous (and financially mobile) than I before making any leaps of Mark/Space faith.