Editors' note: This review was updated on March 26, 2013, to include a feature available only on devices running Android Jelly Bean and higher.
Let me start by saying that Keep is not Google's Evernote killer. Not yet, anyway. It doesn't have nearly the feature set that Evernote does, and it's only available on Android and on the Web through Google Drive. So for now, let's postpone the Evernote comparisons until this newborn app is mature enough to handle itself in a fistfight.
With that in mind, let's evaluate Google Keep for what it actually is: a simple, convenient note-taker for Android.
The obvious best thing about Google Keep is its integration with Google Drive. This ensures that all of your mobile notes get synced through the cloud automatically, and can be accessed from any device -- desktop or mobile -- so long as you have an active Internet connection. This sort of integration is convenient, expected, and reliable. And you can be sure that Google is not stopping here. In fact, I'm guessing the company is right now hard at work, trying to integrate Keep with its other services as well.
Google Keep for Android opens up to a slim toolbar up top that houses pretty much all of the app's functions. Like other note-takers, it gives you buttons to create a text note, checklist, voice, or photo note, right from its dashboard. These buttons, while they do help to get your notes started, do not limit the functionality of your notes in any way, though, and that's important to know. This means that you can actually start a text note, then later add photos or check boxes to it, or start a checklist and later add photos and text to it.
From the Dashboard, you can quickly archive notes by swiping them to the side. Otherwise, you can long-press a note to bring up other options or to move it. One thing I found is that the toolbar on the dashboard exhibits some unpredictable behavior. Sometimes it stays pinned to the top of the screen even as you scroll through your notes, and other times it simply disappears.
The "quick note" field on the toolbar lets you type out a few strings of text and simply tap your keyboard's Return key to save. This is perfect for quick reminders that don't require any formatting at all.