Movie sequels often don't live up to the hype of the original blockbuster, but the same isn't always true of smartphones -- on the contrary, they typically get even better. The Nexus lineup, initially thought of as a "playground" for Android developers to test their apps on, has continually gotten better at its craft (and popularity). Not only that, it's picking up momentum: in less than five months, Google has crafted two Nexus tablets as well as its latest and greatest smartphone
