Gruber asserts.

Being able to label the back button is a big reason why the iPhone’s on-screen buttons are better than Android’s hardware Back button. A dedicated hardware Back button can never answer the question “Where?” Oh really

The Back button on my browser is not labeled in any way, nor are the (to Gruber perhaps confusingly labeled) emergency “exit” signs in most buildings. Some things are just so blindingly obvious they do not warrant a label at all.

I guess I never really considered the “Where?” question to be important. I always figured the Back button on my phone would do pretty much what it says on the tin: take you back. Back to where you came from; wherever that may have been.

Conversely.

When I click my Android hardware Back button after moving from one application to the next (for instance when opening a map, webpage or dialing a number from within an app) Android does exactly what I would expect; it goes back to the previous screen. As long as I keep tapping that button, Android will take me back; even if I have been moving acros a multitude of applications. Right up until I return to the Home screen.*

This makes total sense to me.

When the user presses the BACK key, the current activity is popped from the top of the stack (the activity is destroyed) and the previous activity resumes (the previous state of its UI is restored). Activities in the stack are never rearranged, only pushed and popped from the stack-pushed onto the stack when started by the current activity and popped off when the user leaves it using the BACK key. For me, this consistent Back functionality across applications is a big reason why Android’s Back button is better than the iPhone’s on-screen buttons. Even if they do have fancier labels.

[* As a side note, I’ve always felt the Android applications integrate more often and more nicely producing a more natural flow between apps. Perhaps this point is not a salient to those used to the more clunky iOS flow where manual application switching is more common, at least for me. ]