I dunno really... I just fell in love with her all of a sudden, I think it was in Onna ni Sachi Are, maybe... I'm still not too keen on her vocal abilities, but she's a cutie nonetheless, and she's a very sweet girl, which always makes her top of my list!
I remember people hated on her like crazy during the auditions, and of course, after she got picked, everyone was all like "OMG Demise... Momusu is doomed bla bla bla" I wasn't really favoring any girl during the audition (although I did like the cross eyed girl who did traditional japanese dance with fans, she was cool), and all I wanted was a more than one person generation... And then I watched the video where they tell Aika that she won, and she's so genuinely happy! I kind of started loving her eversince.
Whoa, long post! Anyway, I hate it when people hate on Aika because she's so sweet natured that I feel like she can't defend herself or something XD I mean, if someone hates Reina, she can personally stomp them, if someone hates Koha, she wouldn't care because she's in her own little world and so on... But Aika is just... I dunno, I just feel horrible whenever I read something bad about her.
And Oota Aika IS cuter. I mean, seriously, Tenshi no Shippo almost killed me with cuteness when I watched the preview