Apple Thoughts: Wallet 3 for Mac and iPhone

Can't seem to remember your account for that one site you almost never visit? Need to re-install some software you lost the serial number for? Well, you're in trouble. But had you entered that data in Wallet beforehand, you'd be able to retrieve that information effortlessly.

I have a password/serial number storage system in place already (KeePassX), but Wallet allows you to sync your password database with your iPhone. The iPhone app costs $3.99 and the desktop application costs $20. Seems a small price to pay to be able to sync and carry my passwords anywhere. Probably the best feature is the ability to sync with multiple Macs (and the iPhone) over MobileMe. Is anyone using this, and if so, what has your experience been like?