Honestly? I'm having a bit of a hard time. I really like Ione's astro design, but the tail (or rather, its lack of an actual visible swirl) throws me off. Whenever I look at it, I either want to pencil the swirl in or get a rubber to erase the entire tail, haha...
Sasha is very cute, but feels a little "too cute" for me, if that makes sense. I usually don't aim for characters that are obviously "meant to be" popular, unless I REALLY like them, which is why Shino, for example, is completely uninteresting to me, despite looking great.
With that being said, Petri's design is so cute. Look at the little nose, the glasses and the smile.
Off topic: The discussion about Sasha's actual gender only makes me remember how much I find it sad that villager types are gender locked. I want sweet guys, strong girls, cranky ladies and peppy dudes lol... *sigh*