I played with an Iphone 4s on release and gave Siri the once over. It is indeed a moderate step forward with regard to conversational understanding. However it is clearly a beta and, from my point of view in the UK, unreleasable tech. World phone indeed! I'll go further and say, if Steve Job's had still been CEO, Siri would not have been released in its current state. Its simply proof of concept from Apple.
On my WP7 I can say "find local pizza" or "indian" and it will do just that, and direct me to the location, turn by turn, That doesnt work outside the US with Siri.
Siri understood what we said about 70% of the time, which is no better, if not worse than my WP. I also didnt like the British Siri voice, its a posh bloke. It was amusing to play with though, asking it "open the pod bay doors please" and things like that, but overall its not as good as WP implementation for actually usefullness. It feels a bit like a toy.
Voice control on a phone is useful in certain cercomstances. I can call and text when driving on WP7 and it works great. If My WP pings indicating a new message when Im lying in bed I can say read, I can dictate a reply, and say send, and it just works, most of the time. Overall though I dont see people wanting to control ther phone with voice all the time. Theres background noise and other people to consider and the constant beeping prompting you to speak, so it a little ineligant. I can just imagine being sat in a coffee shop with every one babbling to there phone, clearly and noisily. I think it will be more use in the home. I can imagine getting home and touching a tablet by the door and saying: "lights 50%, oven 200 degrees C, switch the music on in the kitchen" etc ala StarTrek.
So yeah, I do think its a step in the right direction from Apple, but its currently in beta and is buggy, as shocking as it is to hear Apple releasing functionality that doesn't "just work" hehe. I was a little disapointed as I expected it to "just work"
Its not a revolution, that is clear, in fact most of the features of IP4s and IOS5 did not wow me enough to move from Windows Phone, especially with Iphones dated GUI that looks like its from 2006.
It seems the new features Apple have introduced like the message centre, wifi syncing, cloud, and others, we on WP and probably Android too, have been using for months. So its nice to see Apple playing catchup. Competition is good and imitation is one of the nicest form of praise.
So I will continue to take Steves advice, ironically, and "Think different" with my Windows Phone.
Regards