It's based on Vlingo, and offers you the chance to do pretty much everything Siri on the iPhone can do – it even parses Wolfram Alpha to get its information.
But it doesn't have Siri's sense of humor – ask it what its name is, and it will tell you Wolfram Alpha. It won't label the Nokia Lumia 900 as the best phone ever, and it also doesn't know the meaning of life.
However what it can do is simple tasks, such as opening the calendar, making an appointment or start playing a specific song or playlist. You'll have no joy with videos and searching the web can be a bind, but for items like setting a timer or an alarm or activating driving mode, it's perfect.
Well, we say perfect – the speech recognition is still a little bit iffy at times and the network connectivity can be frustratingly slow, but if you're in a car or somewhere else where hands free operation is a must then it's a good tool to have.
Another, larger, problem is the fact S Voice froze the phone a little too regularly, especially when activating it through Bluetooth headset or constantly jumping in and out of the app.
This has sorted itself as an issue largely - and to be honest, we used S Voice so little that it wasn't really an issue.
However, we wish Samsung would get rid of this idea of being able to wake the phone with a certain command – you can do so from the lock screen or the app itself, and you can train to phone to know your own command too.
But when will it ever be needed? If you're turning on the lock screen anyway, you can just press the home key twice to fire up the app, and if you're in it already, just press the blinkin' button at the bottom – we don't need to say anything to the phone.
You can't help but feel that S Voice is nothing more than a 'me too' addition to the phone – you can't do anything cool like take a picture with your voice, so what's the point? In fairness, we've said the same about Siri – it's not a novelty, but it's not a headline feature.
Over the last few months, we haven't used it once since the review, other than trying to set a timer as we have done constantly with an iPhone. It didn't understand what was being said first, then made us confirm the timer. It renders the app pointless.
So to summarise: S Voice is about 80% as good as Siri, given that all we use that for now is setting a timer or making it say funny things.
Update: You can now see S Voice, Google Now and Siri in action and make up your own mind on how good they are in our video face off below.
One of the other big-hitting features Samsung is talking about is the ability to track your eyeballs to make sure the display stays lit when you're looking at it.
In theory this should mean that you can keep the screen timeout to a minimum of fifteen seconds and then never have to worry about it turning off – a little eye icon (eyecon?) appears in the notification bar when it's tracking your peepers.
In practice it works around 75% of the time… even in bright light it can sometimes still turn off the display, despite the icon showing up. In fact, the icon can pop up even when you're wearing sunglasses – so it's hard to trust it.
However, if you're in an evenly-lit space it will generally catch your eye and keep the display on – we just feel it should be completely flawless as a system when you're in a well-lit area.
Update: We've spoken to Samsung about this, and the brand has told us that the reason for both of these features being a little erratic is down to 'optimisation of cutting edge, innovative features' (read: they're new) and promises tweaks may be made in the near future to fix any issue. Here's hoping it's sooner rather than later.
It seems these tweaks haven't worked - Smart Stay still is totally erratic. It's a bonus feature that works to keep the screen on - but when it registers the eye and doesn't stay on, it's really irritating.