Ooh, interesting question.
I'd say she's a pretty mixed bag of traits. As a life-long soldier and invader, she can be quite ruthless and even bloodthirsty at times. Even though she's attracted to humans and has even grown fond of them, she wouldn't have any compunction about killing any if she felt she needed to (which she has demonstrated once or twice already). She also tends to be smug, arrogant, and is prone to pursuing her goals in a manic/overzealous manner. You could also accuse her of being quick to anger.
(She mad horny, too; I feel like that one is evident enough but it's worth mentioning.)
She's terrible at paying attention to things and very often just speaks her mind without really thinking of the consequences; she's a much better at thinking short-term than she is at thinking long-term. That said, when she can be bothered to string two thoughts together she can actually be quite astute, but that's not something she can consistently do.
Prior to being impregnated, she was generally fearless (more for her arrogance and complete lack of awareness than anything else) but she's grown more cautious now that she's a Breeder. Even though she's supremely confident in herself and her abilities, she's an appallingly bad liar and is quick to become flustered if her bluffs are called out. Luckily for her, the humans in my world are even more clueless than she is so it tends to work out.
In spite of her faults and flaws, she does have some more charitable qualities. She can be very compassionate, especially towards her friends and children, and is fiercely loyal to her people. She can even be uncharacteristically supportive towards others (when they're not an obstacle at least). She doesn't necessarily go out of her way to be cruel, it's just kind of a trait that she developed during her tenure as a ground trooper; she can be a real sweetheart when she wants to be.