Lately I've seen a few posts criticizing the Android hardware buttons. I get where they're coming from - especially regarding the sometimes confusing way the back button is handled - but now that I've switched to Android, these buttons are among the things that make it so hard for me to use an iPhone again.
As an Android developer, I love that I can tuck actions into the menu button instead of having to use precious screen real estate for icons that perform those actions, as iPhone developers are forced to do.
Seriously, how many iPhone developers would love to stop fretting over where to place their settings icon, or their accounts icon, or their mark all read icon, etc.? Wouldn't it be nice to have a common place to put all those things so you didn't have to clutter your UI with them?
I'm also a fan of the much-maligned Android back button. Yes, some apps intercept the back button and make it act weird. I hate that, too - which is why I don't use those apps. Those crappy apps aside, I like having an easy, consistent way to navigate between activities and apps.
Now, by this point iPhone users may have written me off as an Android fanboy, but that's not the case. There are plenty of things the iPhone does better than Android - most importantly the iPhone wins on overall UI consistency and attention to detail. But as both a developer and an end user, the hardware buttons make Android easier and simpler for me.