User blog comment:Alekos23/Fairy Tail popularity poll results on the 19th/@comment-4449950-20140716073721/@comment-7418318-20140716080556

She's cute, smart, powerful and mysterious all in one package, when the situation calls for it, she can even pull off an evil look on her face (made all the more intimidating due to the contrast to her usual cuteness) and she's so determinded/dedicated that not even death could stop her from watching over her guild. That's plenty of reason for her to be popular if you ask me.