Tried Siri and does not recognize the difference between the number 2, to, too, two. An email address I use has a number 2 in it and Siri only uses "to". There were other issues when I trie to get it to get that address right but I can't remember what they were. It had other issues with other ways I tried to use it too that I don't remember exactly. I tried in when I got my iPhone 5 a year ago. I have disable it. Have not downloaded the iOS 7 yet. Don't think I will try it with iOS 7.
I use Siri every day to check appointments, weather dial numbers, make appointments look for places in maps play music so just about every thing. I also use voice microphone to create responses to messages and posts. Sometime gets screwed up lol but very useful.
My phone has a password , so mostly when driving instead of unlocking and clicking on a name (Which is dangerous) , I just have to say " Call Whatshisname "
So yes , if only for that , I find Siri very useful !
I see no use of siri but still i belive the feature of siri is much brighter than what it is now.
A siri than adopt my own voice only as comand would be the siri that i would use every sec of my life .