[dasil003]

On my Galaxy Nexus the back button is always in the exact same physical position, which is nice because you can reflexively hit it like a hard button and you won't get caught out in cases where it's transitioning from portrait to landscape or vice versa.

Also, since Jelly Bean I can't say I've ever had an unexpected result by pressing the back button. As far as I can tell it always does The Right Thing since they got their guidelines formalized, at least with the couple dozen apps I regularly use. I have to say on balance I've been more annoyed with iPhone apps lacking necessary navigation buttons on some screens more than Android back button inconsistency.