I really like her passionatly angry side, cursing and swearing and not shying away from conflict. Also there is the mystery about her eyes. And hell yeah, who doesn't love a space pilot??
I honestly wouldn't be able to pick a favourite, all the characters are super interesting. Maybe my favourite would be Emily with her shyness on one hand and a pretty dark streak of bloodlust on the other hand. I still don't know when I can redeem my favour that I won in the shooting contest with her (I think it was in s1?). Or if there will be any serious consequences for letting her kill SAC guys on the station over Malladan (if I remember correctly). Would love to see her embracing that inner darkness a bit more.