Is that siri or android voice commands? You can do those without unlocking the phone? (on android I mean). Is that only with a headset connected? I need to look into this. I'm a traffic hazard typing in my PIN on my phone to change songs or call someone while on the road.
It's not really Siri or Android's Voice Commands - it's the pre-Siri system on an iPhone 4 (and iPhone 3GS).
I never did find a really great way to do it on Android on my SGS2 - the best that I could find was Google Voice Actions, but it didn't do everything that I wanted. Samsung's updated voice command system on the SGS3 is pretty good too - arguably better than Google's default one. Beyond that, there's a lot of Android voice apps available (Jeannie, Voice Actions Plus, etc), but they are mostly trying to emulate Siri and look things up on the web, or giving back amusing comments, but weren't so good on the more basic functionality of doing tasks on the phone and thus weren't of much interest to me.
Back on the original topic, I have to admit that I haven't used Siri all that much because I don't own an iPhone 4S, but back around the time the iPhone 4S was released I bought one and then returned it within the return/exchange window. My primary complaint with the iPhone 4S was that Siri required an internet connection to do even basic tasks that an iPhone 4 could do without a connection. So when I'd be cycling in an area without internet (not uncommon in the foothills west of town) and I'd ask it to play a certain playlist, it wouldn't because it had no internet. Since this is a feature that I use a lot, I found this pretty frustrating because pulling over, unclipping, taking off my gloves, reaching back into my jersey for the phone, unlocking it, navigating to the music player, and selecting a new playlist and undoing all of this to keep riding was so much more work than just slowing down slightly, cupping the microphone on the ear buds and saying "play playlist whatever" and then speeding back up.
But for all that I hated the internet requirement of Siri, I didn't think Siri was totally useless. I thought more than anything what Siri did for the industry and consumers was highlight a different form of user interface. In classic Apple style it was an immensely overhyped feature and, yes, Android had it first, but what I thought Siri did was convince manufacturers and consumers that this is an important feature for some (but clearly not all) users. I really liked the geofencing reminders in Siri and I would occasionally have it (her?) compose a text for me while driving. Siri wasn't useless but it was less than I had hoped. I really wanted the computer on the Starship Enterprise and what I got was a mostly braindead app full of canned, somewhat amusing answers that had an incredible advertising campaign but limited functionality and required an internet connection to do anything useful.
What I really want is Project Majel - or whatever Google is calling it. I want to be driving down the road and be able to hit the bluetooth button in my car and ask my phone to find me any information that I want, answer my questions, check and add appointments to my calendar, tell me the weather tomorrow in Moscow, tell me the square root of 75, tell me the first three lines of chapter 4 of War and Peace, and anything else that I want to know. And I'd like it to be able to do this offline or online and if it's offline to do the best it case with the information that it has locally on the phone. I don't really care if this system can answer questions with silly responses - although my children might be amused - but I really want everything done with voice... at least while I'm driving.