Google's Android 4.2 release may not be a major upgrade, but it sure does have an awful lot of interesting elements.
Aside from the new features, new security system, and new 10-inch tablet UI, Android 4.2 delivers some nice subtle refinements to the Jelly Bean interface. Here are some of the small but meaningful touches I've noticed while testing the Nexus 4 and Nexus 10:
The lock screen
The old 4.1 lock screen is on the left; the new 4.2 version is on the right. Again, we're talking subtleties here, but it's often the little details that make a big difference. The changes in font and alignment here make the system look noticeably sleeker and more inviting.
The notification pulldown
Again, 4.1 is on the left, 4.2 on the right. The day is now abbreviated and placed in line with the date, thereby reducing clutter, and the settings icon now remains permanently justified right (and no longer looks confusingly similar to the dismiss-notifications icon -- something that always bugged me in 4.1).
On large-screen tablets, the difference is even greater. Google has taken advantage of the extra screen real estate and split up the regular notification panel from the new "quick settings" panel (on a phone, the two panels are in the same place).
As you can see, swiping downward on the left side of a 10-inch tablet brings down the standard notification panel, while swiping downward on the right side triggers the "quick settings" panel. This remains true whether you're holding the device in landscape or portrait orientation.
The app switcher
I pointed this one out on Google+ the other day: The Android 4.2 app switcher (a.k.a. the multitasking tool) now appears as a full-screen interface instead of a transparent overlay with content visible behind it. The thumbnails and icons fly into place with a slick-looking new animation. The background, meanwhile, is the same as your current system wallpaper.
The same setup appears on 4.2-level phones, too -- in both landscape and portrait mode.
Gmail
I love the updated Android 4.2 Gmail app; I'm a heavy email user (that is, a guy who uses email heavily -- not a heavy guy who uses email), so the tweaks here make a definite difference for me.
In the image above, you'll see that the old file cabinet archive icon has been replaced with a more modern-looking symbol that matches Gmail's Web interface. What you can't see in that image, though, is that its presence has also expanded: When you're viewing a message within a label, you can now tap the archive button to remove the label and archive the message.
Prior to 4.2, the archive button didn't show up when you were viewing messages within labels; the only way to archive a message was to tap the labels button, manually uncheck the label from the list, and then tap "OK." Needless to say, tapping a single button once is significantly more user-friendly.
Speaking of labels, the Android 4.2 Gmail app also now shows custom label colors (which you can assign in the Web Gmail client) in the top-of-screen dropdown menu. Another subtle but nice addition.
The Gmail app has some great function-based additions, too, including the ability to swipe left or right on a message in your inbox to archive it and the option to have messages automatically formatted to fit your screen with pinch-to-zoom functionality.
Developer options
The vast majority of Android users are not developers and don't need access to developer-level settings, yet those very settings have long lived within the top level of the main Android system settings menu.
With Android 4.2, Google has opted to optimize things for the majority of folks and keep developer options hidden by default. It's understandable, as developer options include advanced tools that most users don't need; their presence could cause confusion and result in some strange-looking options being enabled by mistake.
To enable developer options, all you do is go into the "About phone" menu and tap the "Build number" line seven times. Once you start tapping, the system cheers you along...
...and when you're done, presto-change-o: Developer options are there.
As Android VP of Engineering Hiroshi Lockheimer explained to me when I chatted with him yesterday, the change is part of Google's ongoing effort to make Android more usable and less confusing for the average user. It's an effort that, based on my experiences with Android 4.0, 4.1, and now 4.2, I'd say is very much paying off.
For a broader look at the Android 4.2 experience, check out my massive FAQ and my hands-on impressions of the Nexus 4 and Nexus 10.
I'll have more detailed thoughts on the devices to share with you soon. In the meantime, feel free to come join me on Google+ for more sneak peeks and Android discussion.