I usually don't decide which game I choose to purchase until more version exclusives are announced. That being said, I'm basing my current decision off of Legendary design. The design that I feel is superior to the other is X-Deer's design. It's quite a radiant and unique design, and I fell in love with it at first sight. Y-Bird's design, however, looked just as unique, but not something that sparked my interest.
As of right now, I intend to purchase X version, but my design may or may not change in the future.