Engadget - We just love HTC's One X here at Engadget -- it's quite possibly our favorite smartphone of 2012. Three devices have crossed our desks over the past year -- the original with HSPA+, AT&T's model with LTE and, more recently, the global One X+ with HSPA+. Now the saga continues with AT&T selling its own version of the One X+ with LTE on board. What's different between these handsets? How does AT&T's $200 variant stack up against its global counterpart? Is it worth spending an additional $100 (or more) for AT&T's One X+ versus the original One X? Does the bump in storage (64GB vs. 16GB) make up for the lack of color options?