In fact, it's easiest to tell you what RAGE isn't right away. It's nothing like Fallout 3. It's nothing like Borderlands. It's not an RPG, though Id and Bethesda have used RPG terminology in describing it. It's not much of an open world. It's not very big. It's not very long.
And unfortunately, it's not the return to prominence that Id fans have been hoping for.