I wouldn't worry.
I'm not getting the 4S since I'm ok with my 4, and usually skip every other version.
However - it shouldn't take long before a jailbroken version hits the streets ;-), so... Hold your horses.
I have the current Siri app on my iPhone 4. I have had it since the day it hit the AppStore and it has always performed flawlessly. It is sooo easy to use and saves a LOT of time and typing ... plus it is FUN! I find this simple little app AMAZING ... and am looking forward to using Apple's version on my new 4S! It is a lot like FaceTime ... some people never take advantage of that but I use mine A LOT! If you take advantage of all your phone has to offer and use it in the ways Steve envisioned ... it is a work of art at the very least!
I don't believe the one that was in the app store is the same as that included with the 4S.
And the reports of the 4S's Siri running on an A4 device like the iPhone 4 appear to be premature. One of the two people credited with doing it has essentially said all they did was prove it did not work.
UPDATE: Gojohnnyboi chimed in with this clarification:
[COLOR=#343before5] We didn’t “port” Siri to anything. We investigated it, and verified the claim that it is not able to run on old devices.[/COLOR]
hope it can recognize Chinese well, and I used to dictating texts with a special input method developed by University of Science and Technology of China. But I'm bothering with switching input method frequently and I think it's unnecessary to install an input method only for voice typing.
The voice search may fit me, I will try it on my Acer Liquid, firmware Android 2.3