I don't know what happened to this product, guess I'm still an invitee. Anyway I recently discovered the handsfree "Hey Siri" thing in iOS 8.
Here's how to enable it. I'm sure the speaker on the Amazon Echo would be far superior to my iPad's built-in speaker, but the functionality seems otherwise similar. If the Echo had been available before I discovered this new feature, I would have bought it. Now I'm less interested.