Why these covers? I just love the contrast of colors (dark gray metal vs pink), lines (circular vs rectangular), the overall matte tone, and how Ultron looks; especially in the first 2 covers. Besides, I may not be the biggest fan of the Marvel Universe but I do like alternative realities and tales of the apocalypse so I'm looking forward to this series.
Age of Ultron, 2013 A.U. - variant covers #1-5 by artist Adi Granov (??? see note below):
Here's the next three variant covers of this series... as of May 2013.
Note: I am still not sure if these covers were created by Adi Granov or a South-Korean artist with the alias Rock-he Kim?