The dedicated menu button made navigation in every app not only intuitive but consistent. One of the things that absolutely infuriated me about iOS was playing a game of "Find the settings/back/exit/etc. button" in every single app. The best part is realizing the app's developer didn't include the option you're looking for after 10 minutes of searching, which would be obvious if you tapped the menu button once in Android.
As a Galaxy Nexus user, it's the one feature of my original Droid that I miss the most. Google's "If it ain't broke, break it" strategy is really getting on my nerves lately.
It's not consistent because sometimes the hard menu button shows something and sometimes it doesn't, no one knows. It's also not intuitive that feature xyz is accessed by the menu key. The user has to look for feature xyz, get frustrated, and press the hard menu button as the last resort in their annoying search for it.
As a Galaxy Nexus user, it's the one feature of my original Droid that I miss the most. Google's "If it ain't broke, break it" strategy is really getting on my nerves lately.