If you have an iPhone4 already, you'll probably want to pass on this "upgrade" and wait for the 5, unless you have some discretionary income to burn. There isn't a lot there for a current 4 user, but very tempting for someone contemplating an iPhone.
I went ahead and stayed Android yesterday when I upgraded from my Droid1 to a Droid3. I really like the larger screen, but I thought I wouldn't.
I don't know what all the fuss about Siri is. I have been able to talk to my Droid since I got it two years ago, and the same technology is in our Ford Edge. So uhhh, congratulations on catching up Apple.
-Mike
I'm starting to sound like some kind of Apple fanboy despite my owning and loving Android phone but here I go again :d...
Anywhoozle, Siri is more than simple speech recognition. It's a speech recognizing artificial intelligence capable of completing tasks based entirely on you talking to it as if it were another human being. Hit a button, say a few words and the deed is done as opposed to being able to use speech recognition only here and there on an Android phone.
Here's a video showing how open ended it is and how thoroughly it can interpret your commands.
It's pretty damn schweet... and no I'm not just saying that to appease our soon-to-be robot overlords
.EDIT: I don't think it's leaps and bounds beyond Android's own voice command thingie but it seems like it's more versatile, accurate, and responsive from what I've seen.