Okay, so what else can Google Now, besides the Siri-like basics?
Did you see JR Raphael's piece on 70 things to try with Google Voice Search in Android 4.1? I mean, seriously, some of it is nuts. "What is the temperature of the sun?" "How tall is Will Arnett?" "What is Oracle stock trading at today?" "S-Y-N-C" to get a spoken read-out on a stock. "Navigate to Great Lakes Brewing Company in Cleveland."
What does Google Now not do well?
It definitely has some kinks. In particular, I've found on my devices, in coordinating with other apps.
The built-in text messaging translation ("Text Brian Smith, How about a Cubs game next Friday?") works pretty well, unless you use Google Voice as your text messaging service. Speak a text and tap "Send message," and you'll be asked, in normal fashion, whether to use "Messaging" or "Google Voice" to send it. If you choose Google Voice, there's a very good chance it just won't go through, and you won't ever know it didn't go through. That's been my experience, at least, running a lightly modified Android 4.1 build on a Verizon Galaxy Nexus.
Like Siri, too, Google Now feels magical when it works, and completely moronic when it transcribes seemingly basic words incorrectly, or doesn't understand your context at all. That's the nature of voice recognition.
It seems like you keep interchanging "Voice Search" and "Google Now"
You're right. When you tap the microphone on your home screen and tell your phone to search, do, or answer something, the result comes up in Google Now, the specialized results window that has personalized "cards" along with the standard links. But as noted earlier, if you typed the same thing into Google Now, you'd get the same answers. Voice Search is just (usually) the easiest way to get to Google Now.
Cards. As you use Google Now and carry your phone around, it tries to get smarter about showing you relevant contextual information when you simply bring up Google Now for a glance, rather than for a specific search. The weather nearby and your next calendar appointment (and the time to drive there with traffic figured in) are the defaults. If you allow Google to maintain your Google Web History, you'll also start seeing flights you searched for, sports teams you're interested in, stock updates, and other context.
When will I ever get Google Now?
Probably the next time you buy a new Android device, unless your device is in line to receive an upgrade to Android 4.1.
But, then again, Google has just delivered search results that feature some Google-Now-like context cards. So the real answer may be that you'll get it inside your browser, and then later on, baked into your phone.
What's the distance from the Earth to its moon?
238,900 miles, or 384,400 kilometers, as Google Now just told me in its reassuring robo-female patois.