Apple describes Siri as an "intelligent personal assistant." What is quite revolutionary about it is the fact that you can simply converse with it as you would another human. There is -- supposedly -- no need to alter your speaking tone or use specialized words in order for Siri to recognize your voice. Siri also goes a step further from basic scheduling or reminders. For instance, if you ask Siri to schedule an appointment for you at a specific time but it sees that you are already busy on that date (by reading your calendar) it can offer to reschedule the appointment at a later time. Additionally, due to it's GPS integration, you're able to set reminders to notify you to do something when you reach a destination (like call your mom when you get home). Siri also boasts integration with almost all of iOS 5's native applications. And finally, a big draw with Siri is its ability to compose text and emails. People still continue to complain about iPhone's keypad so this might be their solution for typing long blocks of text. (It is also pretty sassy which is nice.)
But we remain skeptical because we have yet to see a usable voice detection program that has ever risen above the level of sheer novelty. Taking your phone out, opening calendar, and entering a meeting wouldn't take that much time so it's crucial that Siri is able to complete it faster and in a more efficient way. Siri also needs to be highly capable at recognizing your voice, interpreting it, and acting on it quickly. Our biggest issue with voice detection is that it doesn't understand what we say or what we mean. They have also been very finicky about background noise... it typically had to be near silent in order for it to understand us. We're extremely curious just how well Siri will be able to separate background noise from your own speaking voice since that will be a big challenge in assessing Siri's usability.
Lastly, Apple does seem dedicated to Siri's future growth. Apparently Siri will adapt and "learn" your voice the more you use it. And unless we're reading Apple's FAQ wrong, it seems like the new algorithms Siri creates will also be sent back to Apple and will help make Siri better for everyone. So if Siri doesn't work well out of the box, it might just need time as it will get better with age. We're certainly anxious to begin using Siri and we'll start reporting back to you within the next week so keep a look out as we discover together just how practical Apple's "intelligent personal assistant" can be.
(...but let's hope it doesn't get too intelligent.)