Thoughts:

Really like the 'mail to track' interface. Great way to get tracking numbers into the sytem.

I use Delivery Status by Junecloud to track packages. I have to copypasta to get them in; but then it sends me a Growl every time my package's status changes, and I can hit the Dashboard to see where my stuff is and when the estimated delivery date is.

I would need a similar level of functionality; getting an email when the package is actually delivered won't cut it. Something that had a Dashboard/Growl client and an iOS notification client, though: that I'd switch to in a heartbeat.