Android smartphone users will find the Android 3 UI in the Galaxy Tab 10.1 both familiar and strange. Gone are two standard buttons at the bottom of all Android smartphones: Search and Menu. They now appear at the discretion of each application in the upper right of the screen. The standard Home and Back buttons remain at the bottom of the Galaxy Tab screen, though they use entirely different -- and ugly -- icons. These two on-screen buttons and the notification widget take up the entire bottom of the screen, shrinking the available viewing area. (On Android smartphones, these buttons are in the device rather than on-screen, and the notification widgets appear only on the home screens.) This loss of screen real estate especially matters on the Galaxy Tab in landscape orientation, where the widescreen layout already shortens its display area uncomfortably compared to the iPad 2.
In the Galaxy Tab 10.1, Samsung complements Android 3's already nice ability to see thumbnails of active applications with a custom UI element called live panels, which are widgets you can place on a home screen that show the current status of, say, your email inbox or the weather. One aspect of the Android user interface I admire is the at-a-glance indicators showing what is going on in the tablet (system info, battery life, and so on) or in the outside world (such as news and weather); the iPad 2 is more single-minded in that you have to switch to whatever app or website you want to see with that -- and only that -- information.
The Galaxy Tab 10.1's Android 3 tablet OS doesn't suffer the excessive reliance on the Menu button as Android smartphones do. The Galaxy Tab instead uses its larger display area to make relevant controls easily accessible on-screen, as the iPad and iPhone always have.
The Android OS's Settings app can be disorienting, and the white-on-black text is nearly impossible to view in bright daylight. For example, there are two Wi-Fi options: Wi-Fi and Wi-Fi Settings. Tapping Wi-Fi turns off Wi-Fi -- not what I expected. To find a Wi-Fi network, you tap Wi-Fi Settings. After a while I learned the difference, but it was an unnecessary exercise. (Bluetooth is handled in the same awkward manner.) The iPad 2's iOS doesn't let you confuse turning Wi-Fi on or off with selecting a network, thanks to a single location with clearly designated controls.
The good news is that pinching and zooming, as well as autorotation as you turn the device, work equivalently on the Galaxy Tab 10.1's Android OS and iPad 2's iOS. For text entry, I find the iPad 2's on-screen keyboard to be slightly easier to work with than the Galaxy Tab's, with clearer keys and better contextual use of extra keys, such as in the Mail application. Although I appreciate the intent behind the Galaxy Tab's use of Tab and other keys not found on the iPad 2, the result is that the keyboard is not quite full size in landscape orientation (the iPad 2's is) and, thus, a tad difficult for touch-typing. I'm sure I'll eventually get used to it, but it remains an annoying UI decision.