Update #1 9/6/14: It looks like at least some of those who've run out to buy the Moto 360 at retail are already seeing the KGW42N update. Charge your watch, set it up, and you should get the alert.
Thanks to reader Justin for the tip and the photo!
Update #2 9/9/14: The G Watch is now receiving 4.4W.1 as well, though the build number varies slightly (KGW42Q):
Thanks, Devin Arthur.
Google representatives promised a notable update to the Android Wear platform this week, and it looks like Samsung's only non-Tizen watch is first in line. The Gear Live is currently receiving an over-the-air update to Android Wear version 4.4W.1, which includes some much-needed adjustments to the watch interface for Google Maps Navigation and the built-in alarm function.
The OTA update should be going out in batches, but if you've got a custom recovery on your watch or you want to sideload it via ADB (there's a sentence I never thought I'd write) you can download the update ZIP here.
So what does it do? Well, the biggest change is to navigation, which also requires the latest version of Google Maps installed on your phone. Now when initiating a turn-by-turn navigation session from the Gear Live, you're presented with any alternate destinations that Google might have come up with. So if I said "navigate to Best Buy," it would probably show the one ten minutes north as well as the one fifteen minutes south. Scroll through the list and tap to make your selection.
You can also select your preferred method of navigation when you start out, driving, biking, walking, or public transit. Again, just scroll down and select your method and the navigation function should kick in with the appropriate turn-by-turn directions.
Also, the 8.3 update for the Google Maps app now seems to vibrate the watch with each new turn, which should be handy if you're driving and don't have a cradle for your phone. But please remember not to look at your watch while your car is moving. That's bad, m'kay?
Lastly, Android Wear now has a pint-sized analog to the interface seen on your phone when setting a new alarm, instead of a one time only option. When setting a new alarm with an "OK Google" voice command, you can now select a recurring alarm for one or more days of the week. To initiate this, just tap "edit" after giving the voice command.
That's it. Expect the KGW42N build or its equivalent to go out to the LG G Watch soon, and possibly the new Moto 360 units as well (which are shipping and may be available at your local retailers). Future updates should add some cool new features like local Bluetooth music playback from your watch.
Thanks to Patrick Lackemacher and Shawn!