Impressive is in the zen geek part, and also the part that siri can be hacked to do anything that apple didn't intend. This is no direct comparison to lmce project if that is what you are inferring.
I've a bunch of Apple stuff here, also a phone with Siri, and I'm not impressed by Siri itself. That guy didn't even do the legwork.. and then there is his laughable "security through obscurity" approach. Sure, it is nice, but again, not impressive. He's doing a few of http get requests glued to the siri legwork of some other person with a few lines of ruby.. nothing to see here..