User blog comment:SenRima/Reasons for Liking Zero?/@comment-4866818-20120330074404

People pick "Zeki" because of Zero's and Yuki's history together, their closeness, and the fact that Zero is in love with her. Others choose "Yume" because Kaname and Yuki are an actual couple, siblings, and because they both genuinely love each other. However, because of the type of relationship that Kaname and Yuki have, which can sometimes put people at an off point, most turn to "Zeki" because it's actually more reasonable and genuine.

Btw, I'm a Zeki fan, 2. :D