From what I've read you only get partial functionality because Apple's servers will onlY respond to a 4s.. Basically trying to force people to buy one. Siri used to be available on the app store.
Get an Android based phone and get Vlingo. lol I'd say it's 90% as good, but then again, it hasn't been bought out by anyone and doesn't have the cash Apple infused into Siri. I suspect Google may buy it now, we'll see...
I hope not. While it's convenient to speak to a phone and all that crap, I don't want to talk into my phone to do everything, I'd like to input it myself sometimes via keyboard.